Repulpable and recyclable composite packaging articles and related methods

ABSTRACT

A reusable, fiber containing pulp product is described that is highly suited for use in the manufacture of paper products. The reusable, fiber containing pulp product provides a mixture of fibers and small, dense polymer/particle fragments. The polymer/particle fragments within the reusable, fiber containing pulp product have a size range and density that facilitates efficient removal of the polymer/particle fragments using pressure screens.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of allowed U.S. patentapplication Ser. No. 15/877,136, filed Jan. 22, 2018, which is acontinuation application of U.S. patent application Ser. No. 14/211,132,filed Mar. 14, 2014, now abandoned, which claims priority to provisionalapplication Ser. No. 61/879,888, filed on Sep. 19, 2013, and toprovisional application Ser. No. 61/782,291, filed on Mar. 14, 2013. Theentire contents of each of these applications are hereby incorporated byreference herein and made a part of this disclosure.

TECHNICAL FIELD

The present embodiments relate generally to repulpable and recyclablecomposite packaging materials and/or finished packaging structures.

BACKGROUND

Packages and packaging materials for retail and shipping purposes aretypically designed to be sufficiently durable to allow reliable use ofthe materials and protection of packaged goods. For environmental andeconomic reasons, pulping and recycling characteristics are criticalconsiderations in the development of such packages and materials. Otherimportant considerations include barrier performance, heat seal duringfabrication, surface energy, and efficiency in manufacturing.

SUMMARY

The present embodiments have several features, no single one of which issolely responsible for their desirable attributes. Without limiting thescope of the present embodiments as expressed by the claims that follow,their more prominent features now will be discussed briefly. Afterconsidering this discussion, and particularly after reading the sectionentitled “Detailed Description,” one will understand how the features ofthe present embodiments provide the advantages described herein.

Any or all of the below listed aspects may be a part of the presentembodiments:

Mineral particle densities within the polymer matrix of themineral-containing layer may be from about 2.4 g/cm³ to about 4.9 g/cm³.

Mineral particles within the polymer matrix of the mineral-containinglayer may comprise the cube and block class.

Calcium carbonate particles within the polymer matrix of themineral-containing layer may have about 18-80% particle diameters finerthan 6 μm and about 33-96% particle diameters less than 10 μm.

A hardness of mineral particles within the polymer matrix of themineral-containing layer may be from about 2.0 to 4.0 Mohs.

Mineral particles within the polymer matrix of the mineral-containinglayer may have 0.05 to 0.5 maximum % on 325 mesh per ASTM D1199.

Mineral particles within the polymer matrix of the mineral-containinglayer may have a pH from about 8.5 to about 10.5.

The polymer bonding agent(s) within the mineral-containing layer mayhave densities from about 0.908 g/cm³ to about 1.60 g/cm³.

The polymer bonding agent(s) within the mineral-containing layer mayhave a physical melt flow index from about 4 g/m²/10 min to about 16g/m²/10 min.

Minerals may be fully dispersed within the polymer bonding agent matrix.

The polymer bonding agent(s) within the mineral-containing layer mayhave a molecular weight (Mz) from about 150,000 to about 300,000.

The polymer content weight of the mineral-containing layer may be fromabout 3.5 lbs/3 msf to about 50 lbs/3 msf.

The mineral-containing layer may have a modulus from about 1.8 GPa toabout 4.5 GPa.

About 40-60% of the mineral-containing layer may have a coefficient ofthermal expansion from about 1×10⁻⁶ in/in to about 8×10⁻⁶ in/in.

The mineral-containing layer may be applied to the fiber-containinglayer in coat weights from about 3 g/m² to about 20 g/m².

Surfaces of the mineral-containing layer may have a coefficient ofstatic friction from about 0.18 to about 0.59.

The mineral-containing layer may include a mixture of crystalline,semi-crystalline, and amorphous structures.

The polymer bonding agent(s) of the mineral-containing layer may havecrystallinity from about 60% to about 85%.

The mineral-containing layer may contain coupling agents from about0.05% to about 15% by weight.

The mineral-containing layer may contain from about 0.5% to about 10%plastomers and elastomers with densities from about 0.86 g/cm³ to about0.89 g/cm³ per ASTM D 792.

The mineral-containing layer may have differential scanning calorimetry(DSC) melting peaks from about 59° C. to about 110° C.

The mineral-containing layer molecular weight ranges (Mw) may be fromabout 10,000 to about 100,000.

About 10% to about 70% of the mineral-containing layer may have abranching index (g′) of about 0.99 or less as measured at the Z-averagemolecular weight (Mz) of the bonding agent.

The polymer bonding agent(s) of the mineral-containing layer may have anisotactic run length from about 1 to about 40.

The polymer bonding agent(s) of the mineral-containing layer may have aphysical shear rate from about 1 to about 10,000 at temperatures fromabout 180° C. to about 410° C.

The mineral-containing layer may have a basis weight from about 0.5lbs/msf to about 175 lbs/msf.

The polymer bonding agent(s) of the mineral-containing layer may havefrom about 20% to about 60% amorphous structure and from about 20% toabout 55% crystalline structure.

The polymer bonding agent(s) of the mineral-containing layer maycomprise polyethylene having an amorphous fraction from about 40% toabout 85%.

The mineral-containing layer may have a copolymer isotacticity indexfrom about 20% to about 50% as measured by the DSC method.

Mineral particles within the polymer matrix of the mineral-containinglayer may have an average surface area from about 1.0-1.3 m²/g to about1.8-2.3 m²/g.

Mineral particles within the polymer matrix of the mineral-containinglayer may have a Green Hunter reflectance range from about 91% to about97%, and a Blue Hunter reflectance range from about 89% to about 96%.

The fiber-containing layer may contain inorganic mineral coatings andfillers, including without limitation, kaolin clay, mica, silica, TiO₂,and other pigments.

The fiber-containing layer may contain vinyl and polymeric fillers.

A surface smoothness of the fiber-containing layer may be in the rangeof about 150 to about 200 Bekk seconds.

The fiber-containing layer may have an ash content from about 1% toabout 40%.

The fiber-containing layer may have any or all the characteristicspresented in the following table:

Fiber Aspect Ratio (Average)  5-100 Fiber Thickness (Softwood) 1.5-30 mmFiber Thickness (Hardwood) 0.5-30 mm Filled Fiber Content 1% to 30%Fiber Density 0.3-0.7 g/cm² Fiber Diameter 16-42 microns FiberCoarseness 16-42 mg/100 m Fiber Pulp Types Mechanical,Thermo-Mechanical, Chemi- (Single- to Triple-Layered) Thermo-Mechanical,and Chemical Permeability 0.1-110 m² × 10¹⁵ Hydrogen Ion Concentration4.5-10   Tear Strength (Tappi 496, 56-250 402) Tear Resistance (Tappi414) m 49-250 Moisture Content 2%-18% by Weight

The fiber-containing layer may have any or all the characteristicspresented in the following table:

Tear Burst Fiber Weight Resistance Strength (lbs/3 msf) g/m² (Mn)Surface Roughness (kPa) 40-75  60-110 400-700 2.0-5.5 μm 140-300 75110-130 650-750 2.0-3.5 μm 175-400 115 180-190 1400-1900 100-2500mls/min 175-475 130 205-215 1600-2200 100-2500 mls/min 250-675 200315-330 1900-3200 100-2500 mls/min 500-950 300 460-195  500-4000100-2500 mls/min  700-1850

The mineral-containing layer may comprise a multilayer coextrusion, suchas up to six layers, with each layer having from about 0% to about 70%by weight mineral content with a polymer bonding agent.

A weight of the overall composite may be from about 2.5 lbs/3 msf toabout 150 lbs/3 msf.

The polymer bonding agent(s) of the mineral-containing layer maycomprise linear, branched, and/or highly branched polymers.

The polymer bonding agent(s) of the mineral-containing layer maycomprise polyolefin(s) having a number average molecular weightdistributions (Mn) from about 5,500 to about 13,000, a weight averagemolecular weight (Mz) from about 170,000 to about 490,000, and/or aZ-average molecular weight (Mz) from about 170,000 to about 450,000.

The mineral-containing layer may have a Mw/Mn ratio from about 6.50 toabout 9.50.

The mineral particles within the polymer matrix of themineral-containing layer may be surface treated at levels from about 1.6to about 3.5 mg surface agent/m² of the particle.

The mineral particles within the polymer matrix of themineral-containing layer may have a particle top cut from about d98 of4-15 microns and a surface area from about 3.3 m²/g to about 10 m²/g.

The mineral particles within the polymer matrix of themineral-containing layer may comprise CaCO₃ coated with fatty acidshaving from about 8 to about 24 carbon atoms, with a surface treatmentlevel from about 0.6% to about 1.5% by weight of the treatment, or fromabout 90% to about 99% by weight of the CaCO₃.

The mineral-containing layer may be from about 0.5 mil thick to about 5mil thick.

Examples of non-fiber content in the fiber-containing layer include, butare not limited to, about 50-95% of #1 clay or #1 fine clay, about 3-20%by part calcined clay, about 3-40% by part TiO₂, about 2-45% vinylacrylic, and from about 1% to about 35% protein binders, co-binders, ortri-binders.

The mineral-containing layer may contain incremental quartz-silicacontent.

A process for recycling the present composite structure may have rejectrates from about 10% to about 25% by weight of the starting composite,and screen plate efficiencies from about 60% to about 100%, with screenplates having the option of using hole, slotted, and contoured screenswith one screen behind the other with an A plate having the smallestperforations, an intermediary B plate, and a C plate having the largestperforations, using processes including high density, forward, andthrough flow cleaners having a diameter from about 70 mm to about 400 mmand particle process out of fibers having reject rates of about 0.1% toabout 30% and a particle removal efficiency from about 50% to 90% bymass, and particle sizes from about 150 microns to 0.05 microns.

A process for recycling the present composite structure may havefeed-accept pressures in the range of about 2 kPa to about 12 kPa onsmooth contoured and heavily contoured screens.

The present composite materials may have a pulper consistency from about3% to about 30%, pulping temperatures from about 100° F. to about 200°F., pulping times from about 10 min. to about 60 min., with pulping pHfrom about 6 to about 9.5±0.5, and screen holes from about 0.050″ toabout 0.075″ and slots from about 0.006″ to about 0.020″, drum pulpinghaving an RPM from about 9 to about 20, having 4 mm to about 8 mm holes,with hole-type screens with holes from about 0.8 mm to about 1.5 mm insize, coarse to fine screen holes and slots from about 0.150 mm to about2.8 mm, and screen rotor circumference speeds from about 10 m/s to about30 m/s.

Certain of the present embodiments comprise a recyclable compositepackaging structure. The structure comprises a fiber-containing layer,and a barrier layer bonded to the fiber-containing layer. The barrierlayer includes mineral particles evenly dispersed in a matrix of apolyolefin bonding agent. The barrier layer has a basis weight fromabout 4 lbs/3 msf to about 60 lbs/3 msf, a density from about 1.10 g/cm³to about 1.75 g/cm³, and a caliper from about 0.30 mil to about 3 mil.The barrier layer may be extruded. The fiber-containing layer may have acaliper from about 0.010″ to about 0.030″ and a basis weight from about136 lbs/3 msf to about 286 lbs/3 msf. The barrier layer may have apolyolefin content from about 30% to about 70% by weight. The recyclablecomposite packaging structure may comprise about 1% to about 40%inorganic matter. The recyclable composite packaging structure maycomprise a total repulping recovery up to 98%. The mineral particles maycomprise diatomaceous earth with ultrafine nanoparticles havingdensities from about 2.4 g/cm³ to about 4.9 g/cm³ and particle sizesfrom about 100 nm to about 10 μm. The polyolefin bonding agent may havemolecular weights from about Mw 10,000 to about Mw 100,000 and abranching index (g′) from about 0.99 to about 0.65 as measured at theZ-average molecular weight (Mz) of the polymer. The polyolefin bondingagent may have an isotactic run length from about 1 to about 40. Thepolyolefin bonding agent may have a shear rate from about 1 to about10,000 at temperatures from about 180° C. to about 410° C. The mineralparticles may be cube or block particles. The mineral particles may havean average surface area from about 1-1.3 m²/g to about 1.8-2.3 m²/g. Themineral particles may comprise calcium carbonate particles having fromabout 18%-80% particle diameters finer than 6 μm and from about 33%-96%particle diameters less than 10 μm and top cut from about d98 of 4-15 μmand a surface area from about 3.3 m²/g to about 10 m²/g, a surfacetreatment level from about 0.6% to about 1.5% by weight of treatmentagent or about 99% by weight of the calcium carbonate. Thefiber-containing layer may comprise nano-cellulose having a crystallinecontent from about 40% to about 70%, including nano-fibrils,micro-fibrils, and non-fibril bundles having lateral dimensions fromabout 4 nm to about 30 nm and highly crystalline nano-whiskers fromabout 100 nm to about 1,000 nm, with fiber widths from about 3 nm toabout 15 nm, having charge densities from about 0.5 meq/g to about 1.5meq/g, and the nano-cellulose having a stiffness from about 140 GPa toabout 220 GPa and a tensile strength from about 400 MPa to about 600MPa. Some of the mineral particles may contain fatty acid and stearatecoatings having a Hunter reflectance (green) from about 91% to about97%, a Hunter reflectance (blue) from about 89% to about 96%, a Mohshardness from about 2.75 to about 4.0, a particle pH in water, 5%slurry, at 23° C., from about 8.5 to about 10.5, a particle resistancein water, at 23° C., from about 5,000 ohms to about 25,000 ohms, an ASTMD1199 maximum percentage on a 325 mesh from about 0.05 to about 0.5, avolume resistivity at 20° C. of 10⁹ to about 10¹¹ ohms, a standard heatof formation from its elements at 25° C. from about 288.45 to about288.49 kg-cal/mole, a standard free energy of formation from itselements from about 269.53 to about 269.78 kg-cal/mole, a specific heat1 g 1° C. (between 0° C. and 100° C.) from about 0.200 to about 0.214, aheat conductivity of about 0.0071 g-ca/sec/cm2/1 cm thick at 20° C., acoefficient of linear expansion C=9×10⁻⁶ at 25° C. to 100° C. andC=11.7×10 at 25° C. to 100° C. The fiber-containing layer may comprisevinyl and inorganic mineral coatings and fillers. The fiber-containinglayer may have a surface smoothness from about 1.50 to about 3.15, asmoothness from about 150 to about 200 Bekk-seconds, an ash content fromabout 1% to about 40% by weight, a static friction coefficient μ_(s)from about 0.02 to about 0.50, and a cellulose content having thermalconductivity from about 0.034 to about 0.05 W/mk. Some virgin andrecycled fiber types within the fiber-containing layer may includemechanical, thermo-mechanical, chemo-thermo-mechanical, and chemicalhaving an average aspect ratio from about 5 to about 100, a softwoodfiber thickness from about 1.5 mm to about 30 mm, a hardwood fiberthickness from about 0.5 mm to about 30 mm, a filled fiber content fromabout 1% to about 30%, a density from about 0.3 g/cm³ to about 0.7g/cm³, fiber diameters from about 16 μm to about 42 μm, a fibercoarseness from about 16 mg/100 m to about 42 mg/100 m, a permeabilityfrom about 0.1×10¹⁵ m² to about 110×10¹⁵ m², a hydrogen ionconcentration from about 4.5 to about 10, a Tappi 496, 402 tear strengthfrom about 56 to about 250, a Tappi 414 tear resistance from about m49to about m250, and a moisture content from about 2% to about 18% byweight. The fiber-containing layer may comprise a combination ofrecycled fiber, virgin fiber, thermo-mechanical pulp “TMP,” virgin kraftfiber, clay coated craft fiber, clay coated unbleached kraft fiber, andsolid bleached sulfate fiber. The barrier layer may comprise Tappi T410weights from about 5.5 g/m² to about 52.2 g/m², Tappi T464 moisturebarrier values from about 0.46 g/100 in² to about 37.7 g/100 in², TappiT441 Cobb 2-minute water absorption from about 0.00 to about 0.40, T44130-minute water absorption from about 0.00 to about 0.45, and a TappiT559 grease resistance of 12.0.

Certain of the present embodiments comprise a method of making arecyclable composite packaging structure including a fiber-containinglayer and a mineral-containing layer. The method comprises extrusioncoating the mineral-containing layer onto the fiber-containing layerusing a mineral-containing resin having mineral particles interspersedwithin a polyolefin bonding agent. The extrusion process is carried outunder the following conditions: the resin having a melt flow index fromabout 4 g/10 min. to about 16 g/10 min.; a melt temperature from about440° F. to about 640° F.; an extruder screw or tube barrel pressure fromabout 1,200 psi to about 2,500 psi; an air gap from about 4″ to about16″; a die gap from about 0.020″ to about 0.050″; barrel and die zonetemperatures from about 400° F. to about 640° F.; an extrusion linespeed from about 100 FPM to about 3,500 FPM; and an extrusion laminationline speed from about 100 FPM to about 3,500 FPM. The mineral-containingresin may comprise between 20% and 70% mineral content by weight. Themineral-containing resin may comprise pellets. The mineral-containinglayer may be applied to the fiber-containing layer in coat weights fromabout 41 lbs/3 msf to about 30 lbs/3 msf. The recyclable compositepackaging structure may not contain water-based dispersions, aqueousdispersions, aqueous coatings, emulsions, emulsion-containing coatings,water-containing dispersions, press-line applications, or off-linemixing processes. The mineral-containing layer, weighing from about 15g/m² to about 50 g/m², may be coextruded in line on an extrusion coatingmachine and bonded by extrusion to the fiber-containing layer. Themineral-containing layer may have a density from about 1.22 g/cm³ toabout 1.41 g/cm³. The mineral-containing layer may be from about 25% toabout 75% amorphous and have a water vapor transmission rate (WVTR)under tropical conditions from about 5 gm/m² per day to about 22 g/m²per day.

BRIEF DESCRIPTION OF THE DRAWINGS

The present embodiments now will be discussed in detail with an emphasison highlighting the advantageous features. These embodiments depict thenovel and non-obvious repulpable and recyclable composite packagingarticles and related methods shown in the accompanying drawings, whichare for illustrative purposes only. These drawings include the followingfigures, in which like numerals indicate like parts:

FIG. 1 is a schematic side cross-sectional view of a multilayerrepulpable packaging composite material according to the presentembodiments;

FIG. 1A is a detail view of the portion of FIG. 1 indicated by thecircle 1A-1A;

FIG. 2 is a schematic side cross-sectional view of another multilayerrepulpable packaging composite material according to the presentembodiments;

FIG. 3 is a schematic side cross-sectional view of a repulpablemineral-containing material according to the present embodiments;

FIG. 4 is a schematic detail view of a pellet of a mineral-containingresin with mineral particles interspersed within a bonding agentaccording to the present embodiments;

FIG. 5 is a schematic side cross-sectional view of another multilayerrepulpable packaging composite material according to the presentembodiments; and

FIG. 6 is a schematic side cross-sectional view of another multilayerrepulpable packaging composite material according to the presentembodiments;

FIG. 7 is a container formed from a composite material according to thepresent embodiments;

FIG. 8 is a container liner formed from a composite material accordingto the present embodiments;

FIG. 9 is an envelope formed from a composite material according to thepresent embodiments; and

FIG. 10 is a display tray formed from a composite material according tothe present embodiments.

FIG. 11 depicts a distribution of acceptances from example 6.

FIG. 12 depicts a total ion spectrum of DCM Extract from a washoutfraction of sample CLWR-2.

DETAILED DESCRIPTION

The present embodiments relate to methods and compositions providingrepulpable and recyclable consumer packaging for containing, for exampleand without limitation, food products, dry goods, detergents, etc. Moreparticularly, the present embodiments include using mineral-containinglayer(s), minerals bonded by thermoplastic polymers and subsequentlyadhered to fiber-containing layer(s) using extrusion coating, extrusionlamination, or lamination adhering the mineral-containing layercontinuously and substantially to the surface or surfaces of naturalfiber-containing layers such that the finished package can beeffectively repulped and recycled using both pre-consumer andpost-consumer collection methods. The present embodiments providereusable pulp, thus offering reusability and reprocess ability intovaluable recycled paper-containing packaging products. The presentpackaging composites can be used to form one or more layers of all typesof single-layer and multilayer packaging structures, e.g. foldingcartons and the like, including single-wall or multi-wall corrugatedstructures using the composite packaging material as one or more inneror outer liner(s) and/or corrugated medium(s).

It is current practice, for example, to add a film of polyethylene (PE),polypropylene (PP), polyester, wax, or polyvinylidene chloride (PVDC) onpaper substrates to provide a moisture barrier. Also, various types ofemulsion and aqueous coatings are applied to paper substrates for thesame reason. However, it is believed that there are no repulpable andrecyclable solutions that offer the efficiencies of high speedthermoplastic extrusion coating of mineral-containing pellets forming alayer. The present embodiments provide finished composite materialshaving high barrier performance, heat sealability, high performanceadhesion to fiber, strength, repulpability, and low cost of manufacture.Further, other resins may be used to give packaging materials barrierperformance, such as polyacrylates, polyvinyl acetates, and the like.However, these materials are more expensive than wax, polyethylene andPVDC. Predominantly, barrier alternatives are considered by recycling(repulping) mills to be non-repulpable, mainly because they introducequality problems in the fiber recovery process, either by upsetting theprocess, e.g. by plugging filter screens, or by contaminating thefinished product. Approximately 20% of known paperboards are laminatedwith the materials listed above, or similar materials, resulting inproducts that are incompatible within the recycling industry.

A major drawback to polyolefin and other polymer coatings, such as wax,acrylic, polyethylene terephthalate (PET) dispersions, and PVDC barrierlayers, is that they are either difficult to reprocess or recycle andusually discarded, or they can only be processed at a recycling millwith specialized equipment, or, if processible, provide inferior barrierand heat seal performance for packaging articles such as cups or heatsealed folding cartons. For environmental and cost reasons, the disposalof moisture barrier packaging materials has become an important issuefor paper mills and their customers. Repulping these materials posesspecial problems for the industry. The moisture barrier layer manifestsproblems in recovering the useful fiber from the package. Presently,nearly all of these packages are ultimately discarded into landfills orincinerated, which raises issues with respect to the environment andpublic health, particularly for PVDC. Reprocessing packaging to recoverwood fibers is an important source of wood fibers, and helps avoid wasteof high quality and costly fibers.

When forming packaging that contains food products and dry goods, heatsealability is often important for closures. Also, the packagingstructure preferably provides a barrier for moisture, oxygen, oils, andfatty acids. Other desirable characteristics include mechanicalperformance, aesthetics, cosmetics, resistance to chemicals,recyclability, heat sealability, surface energy, ink adhesion, inkwet-ability, film adhesion to fibers, improved surface for glue andadhesive application, and barrier performance (against oxygen, water,moisture, etc.). Therefore, extrusion coating fiber surfaces usingpolymers, (polyolefins being the most common) and bio-polymers is commonpractice.

Two methods are commonly used for reprocessing wood fibers. The firstmethod breaks up the source of wood fibers, such as packaging materials,by repulping, while other materials are filtered out. The second methodbreaks up the packaging materials such that any non-fibrous materialbreaks up into tiny pieces (generally smaller than 1.6 mm), which thenpass through the filter screen(s) with the wood fibers to constitute apulp. This second method is frequently carried out with chemicaladditives and/or additional equipment, making it expensive and thereforeundesirable.

However, no known resins, with our without wax, used in high-performancebarrier layers, can be reprocessed without additional manufacturingsteps. Recycling these materials is therefore difficult if notimpossible. Additionally, the presence of wax in resins frequentlyresults in a lower quantity of usable pulp, and therefore increases theamount of waste. In the repulping process, waste materials may break upinto very tiny particles, often smaller than 0.7 mm. These particlespass through the filter screen(s) and contaminate pulp that is sent tothe paper machine. Problems repulping wax include clogging the felts,gumming up the can dryer causing web breaks, sticky related unacceptablepaper surface cosmetics, and yield reduction.

The repulping of PE and PP barrier layers (as with most polymers) isvery difficult. During reprocessing, while polyolefin is in the pulper,it separates from the fiber and the polyolefin breaks into large pieceswith estimated widths from about 0.3 cm to 3.0 cm, or larger pieces andparticles having densities in a range from about 0.875 g/cm³ to about0.995 g/cm³ and higher. These pieces cause screen plugging, requiringexpensive downtime to clean, and generate solid waste. However,mineralized layers when repulped break down into a preponderance of fromabout 35% to about 99% of much smaller and more dense fragments in sizesof from about 0.0005 mm² to about 2 mm² or larger, having densities fromabout 1.10 g/cm³ to about 4.75 g/cm³. These unique particles provideimproved repulping and recycling processing benefits. Therefore, themineral-containing layers can be applied successfully tofiber-containing layers with improved re-pulpability vs. polymer layerswith mineral-containing layers applied in coat weights in the range offrom about 4 lbs/msf (pounds per thousand square feet) to about 25lbs/msf. The processing of the mineralized layer composite material canbe accomplished using industry standard repulping and recyclingequipment, much of which is further described in this specification.

Also, for normal processing it is important for the recycler to use astandard pulper equipped with a steam line, using typical screens ofvarious sizes and an operating centrifuge. PVDC coating also hasgenerally the same processing issues as PE. Further, other options suchas emulsion and aqueous coating with vinyl content cannot providecomparable barrier performance or high performance heat sealability atlow cost. Also, mixing at the point of manufacture is often required andsingle or multiple layers of vinyl plus separate layers for minerals,for example, may be required. Also, unlike polyolefins, barrier failureis quite common using these types of layers at points of package stressor fracture during converting or subsequent use. Finally, PVDC andrelated coatings provide major environmental toxic hazards and aretherefore a poor option as a barrier layer.

During repulping, non-fibrous barrier layers must be structurallybrittle enough to break into small enough pieces to ensure the fibersefficiently release from the barrier layer and pass through thescreen(s). Also, the pulped barrier layer fragments must not be toosmall to pass through the screen(s) and create process difficulties inthe paper making machine. Finally, the pulped barrier layer piecescannot be so large as to clog the screen(s) and foul the filteringprocess.

By introducing mineral content into a thermoplastic barrier layer usingproper particle specifications and proper amounts of minerals added, themineral-containing polyolefin layer obtains structural attributesproviding for efficient, clean, and proper processing during the pulpingprocess. Also, a 20%-70% mineralized layer easily releases fiber contentthrough the screen(s), resulting in high fiber yields. Further, by usingan extrusion coated thermoplastic, high speed, efficient productionapplying the barrier layer to the fiber can be enjoyed using commonprocesses such as extrusion coating. Without the need for water based orother dispersions, press line applications, emulsions, or use of singleor multiple layers containing vinyl, adjunct or additional layers ofsimilar materials or minerals, the thermoplastic content acts as abonding agent for the particles, bonding the mineral particles together,fixing them in position in a compounded thermoplastic andmineral-containing resin pellet, heated at temperatures above 400° F.,and extrusion coated in-line on a single piece of equipment andextrusion laminated on a single piece of equipment at high speeds fromabout 100 FPM (feet per minute) up to about 3,500 FPM on paper rolls upto and over from about 30″ to about 140″ wide. The mineral-containinglayer resin is extruded as a pre-mixed or master batch pellet, and assuch the layer maintains its original integrity after extrusion.Therefore, unlike aqueous or emulsion coatings, no mixing is requiredprior to coating, and drying is not required during production at thepoint of printing and converting. The mineralized polyolefin or polymerlayer provides additional benefits, such as high speed heat sealing andimproved barrier performance. Additional benefits may include anexcellent surface for the application of room temperature and hot meltadhesives when forming a package and high levels of moisture, oil, andfatty acid barrier performance.

The fiber component of the repulpable composite may comprise softwoodfibers, hardwood fibers, or a mixture thereof. For example, the papersubstrate may comprise from about 5% to about 95% (such as from about25% to about 90%) softwood fibers and from about 5% to about 95% (suchas from about 25% to about 90%) hardwood fibers. Paper substrates mayalso have, for example, a basis weight of from about 30 to about 200lbs/3000 sq. ft and a caliper (thickness) of from about 0.006″ to about0.048″.

During paper repulping and processing, the fibers are subjected to acleansing and filtering process provided by one or more screens, thusremoving unwanted materials from the re-pulped fiber. Screen plates arecommonly designed to be either hole, slotted, or contoured screens. Theamount and type of rejected and removed material can have an impact onscreen cleanliness. If the screens become clogged, they fail to functionand must be cleaned, creating expensive downtime during processing. Theplates are normally found one behind another with an A plate having thesmallest perforations, an intermediary B plate, and often a C platehaving the largest perforations. Because of the size and conformation ofplastic coating fragments generated during repulping, the plasticrejects clog and dirty the screening system, creating downtime andgeneral inability to process efficiently. However, mineral-containinglayers create dense particles from about 5 mm² to about 0.01 mm².Therefore, based upon reject rates from about 10% to about 25% by weightof the starting paper, the screen cleanliness efficiency achieved can befrom about 60% to about 100%, including pressure screen devices.Further, the pressure drop, expressed as Feed-Accept pressure, can rangefrom about 2 kPa to about 12 kPa on smooth, contoured, or heavilycontoured screens.

Post screen processing includes centrifugal cleaning of the screenaccepts. This pulp cleaning process uses fluid pressure to createrotational fluid motion in a tapered cylinder, causing denser particlesto move outside faster than lighter particles. During cleaning, goodfiber yields are carried inward and upward to the accepted stock inlet.Impurities such as dirt, metals, inks, sand, and any impurities are heldin the downward current and removed from the bottom of the cleaner.Mineral-containing layer impurities found in fiber accepts and rejectshave a density of from about 1.01 g/cm³ to about 4.25 g/cm³. Because theparticles have large density differences from water, and sizecharacteristics, the particles are effectively removed and cleaned fromthe accepts during cleaning. The mineral-containing impurities processout of the fiber accepts efficiently in High Density, Forward, andThrough Flow cleaners, the cleaners having a diameter of from about 70mm to about 400 mm. Further, these particles process out of fibershaving reject rates on or about 0.1-1% to about 5-30%. Additionally,because some particles are typically somewhat spherical in shape (CwAp)they separate more efficiently during centrifugal cleaning. Finally,because the particles are smaller in size and generally dense, they canoften achieve a removal efficiency of from about 50% to about 95% bymass, particle sizes of from about 150 microns to about 0.05 micronsusing singularly or in combination, specific gravity activatedcentrifugal cleaners, flotation washers, and ultra-dispersion washing,the repulpable and recyclable composite material having a pulperconsistency of from about 3% to about 30%, pulping temperatures of fromabout 100° F. to about 200° F., and pulping times of from about 10minutes to about 60 minutes, with pulping pH from about 6 to about9.5±0.5. Process pressure screens can have holes from about 0.050″ toabout 0.075″ with slots from about 0.006″ to about 0.020″.

Table 1, below, illustrates estimated repulpability ranges of acomposite containing paper layer(s) combined with mineralized layer(s).The chart is also applicable when using paper layer(s) fiber finecontent from about 0.5% to 60% by weight of the paper. This data iscongruent using various pulping batch and continuous pulping methodsincluding low consistency continuous, rotor de-trashing, drum pulpinghaving 9-20 RPM, high consistency drum pulping, and drum pulpingcontaining 4 mm to 8 mm holes, pulping consistency from about 3% toabout 20%, also, using disk, pressure, and cylindrical screen types withhole type screen openings from about 0.8 mm to about 1.5 mm and slot andcontoured type openings from about 0.1 mm to about 0.4 mm, furtherincluding coarse to fine screen holes and slots from about 0.150 mm toabout 2.8 mm, and screen rotor circumference speeds from about 10meters/second (m/s) to about 30 m/s.

TABLE 1 Composite Repulpability Mineral Thermo- Cal- Content plasticScreen Total iper lbs/ of Barrier Bonding Yield Inorganic Overall (in.)3 msf Layer(s) Agent (Accepts) Matter Recovery 0.010 136 30%-65% 30%-70%60%-90% 1%-40% 70%-95% 0.012 157 30%-65% 30%-70% 60%-90% 1%-40% 70%-98%0.014 172 30%-65% 30%-70% 60%-90% 1%-40% 70%-98% 0.016 190 30%-65%30%-70% 60%-90% 1%-40% 70%-98% 0.018 208 30%-65% 30%-70% 60%-90% 1%-40%70%-98% 0.020 220 30%-65% 30%-70% 60%-90% 1%-40% 70%-98% 0.022 24130%-65% 30%-70% 60%-90% 1%-40% 70%-98% 0.024 259 30%-65% 30%-70% 60%-90%1%-40% 70%-98% 0.026 268 30%-65% 30%-70% 60%-90% 1%-40% 70%-98% 0.028276 30%-65% 30%-70% 60%-90% 1%-40% 70%-98% 0.030 286 30%-65% 30%-70%60%-90% 1%-40% 70%-98% Note: Percentages are “by weight” of the totalcomposition. MSF is “thousand square feet.” % of inorganic matter isbased upon industry standard ash tests. Repulpability data per Tappi andFibre Box Association industry standard testing and Georgia Tech IPSTreporting.

Various diatomaceous earth mineral fillers and pigments are availablefor use within the repulpable mineral-containing layer within thecomposite structure including mica, silica, clay, kaolin, calciumcarbonate, dolomite, and titanium dioxide to name a few. The fillersoffer improved performance for barrier, opacity, increased stiffness,thermal conductivity, and strength. Fillers are normally less expensivethan polymers and are therefore a very economical component of thepolymer layer. The most commonly used mineral fillers have densities inthe range of 2.4 g/cm³ to 4.9 g/cm³. Most polymers have densities in therange of 0.8 g/cm³ to 1.85 g/cm³ and many can be used as thermoplasticbonding agents.

Filler particles can vary in size and shape. Size can vary from 0.1micron to 10.0 micron mean particle size. An example of very finemineral particles include nano-precipitated calcium carbonate which areless than 100 nanometers in size. Ultrafine nanoparticles can range from0.06 microns to 0.15 microns. These ultrafine particles are useful forcontrolling rheological properties such as viscosity, sag, and slump.Mineral filler particles can have various shapes including e.g. spheres,rods, cubes, blocks, flakes, platelets, and irregular shapes of variousproportions. The relationship between the particles' largest andsmallest dimensions is known as aspect ratio. Together, aspect ratio andshape significantly impact the particles' effect in a composite polymermatrix. In yet other examples, particle hardness relates to coarseness,color to layer cosmetics and opacity. Particle morphology suited for thepresent embodiments are primarily, but not limited to, the cube andblock shapes of salt and calcite having the characteristics shown inTable 2, below. Examples of cubic structures include calcite andfeldspar. Examples of block structures include calcite, feldspar,silica, barite, and nephelite.

TABLE 2 Mineral Physical Properties PARTICLE CLASS CUBE BLOCK TypeCubic, Prismatic, Tabular, Prismatic, Aspect/Shape Ratios: RhombohedralPinacoid, Irregular Length ~1 1.4-4  Width ~1 1 Thickness ~1  1-<1Sedimentation esd esd Surface Area Equivalence 1.24 1.26-1.5

Mineral particles also often have higher specific gravity than polymers.Therefore, the density increases cost through elevated weight. Manyparticles are surface treated with fatty acids or other organicmaterials, such as stearic acid and other materials to improve polymerdispersion during compounding. Surface treatments also affect dry flowproperties, reduce surface absorption, and alter processingcharacteristics. The specific gravity range potential of the mineralsused in the present embodiments including pigments are from about 1.8 toabout 4.85 g/cm³.

It is advantageous to disperse fillers and pigments (which provideopacity and whiteness to the polymer composite) effectively in order toobtain good performance. For fillers, impact strength, gloss, and otherproperties are improved by good dispersion. For pigments, streakingindicates uneven dispersion, whereas a loss in tinting strength may beobserved if the pigment is not fully de-agglomerated. Agglomerates actas flaws that can initiate crack formation and thus lower impactstrength. In the present embodiments, agglomerates are preferably lessthan about 30 microns to preferably less than about 10 microns in size.

Resin and composite extrudate sensitivity to heat becomes importantduring extrusion coating and extrusion lamination production. Smallalterations during processing have an outsized impact upon pre- andpost-extrusion results. Table 3 is a sample, but not limited to,extrusion coating production ranges for identified mineral-filledresins. In Table 3, the melt index measurements were stated under theguidelines of ASTM method D1238-04, and the density measured under theguidelines of ASTM standard method D1501-03.

TABLE 3 Operating Parameters, Mineralized Composite Resins, Monolayer,Coextrusion, and Multilayer Mineral-Containing Composites, toFiber-Containing Layers ROLL 

Extruder #2-#6 Maximum ranges Comments (coextrusion) or Plus & Minus asa % below do not Extruder #1 separate downstream of stated value orrepresent Monolayer units stated value limitations RESIN Earth CoatingEarth Coating SUPPLIER Standridge Color Standridge Color GRADE NUMBERTBD TBD MELT FLOW - Carrier EST: 16 g/10 min. EST: 16 g/10 min. 4 g10/min to 16 g/10 min Interspersed and Resin(s)/bonding agentnon-interspersed COMPOUND DENSITY 1.25 g/cm³ 1.25 g/cm³ 1.01-4.90 g/cm³Molecular weight from (Mz 150,00 to 300,000) MINERAL CONTENT 40% 40%General mineral Interspersed and content 15-60% by weightnon-interspersed MELT TEMPERATURE 590° F. (307° C.) TBD ±20% DESIREDBARREL PRESS. 1600-2200 psi TBD 1200-2500 psi From 1 to 6 extrudersComposite Melt Flow 2-12 g/10 min 2-12 g/10 min  2 g/10 min-14 g/10 minInterspersed and Non-interspersed Air Gap 8″  4″-12″  4″-16″ Die Gap0.025″-0.030″ 0.025″-0.040″ 0.020″-0.050″ From 1 to 6 CoextrusionMonolayer and Coextrusion or separate downstream #2-#6 Co-layersTEMPERATURE SETTINGS Maximum Maximum Initial Settings AdjustmentAdjustment Barrel Zones Barrel Zones Settings Die Zone Die Zone MeltTemperature 590° F. Up to ±25% BARREL ZONE #1 405° F. Up to ±35% DieZone 1 585° F. ± 25% BARREL ZONE #2 540° F. Up to ±35% Die Zones 2-10(as 595° F. ± 25% applicable to equipment) BARREL ZONE #3 575° F. Up to±35% Die Zone 11 (as 585° F. ± 35% applicable to equipment) BARREL ZONE#4 590° F. Up to ±35% BARREL ZONE #5 590° F. Up to ±35% Other barrelZones, if 590° F. Up to ±35% Other die zones if Up to ±35% applicable onspecific applicable equipment

Molecular chains in crystalline areas are arranged somewhat parallel toeach other. In amorphous areas they are random. This mixture ofcrystalline and amorphous regions is essential to the extrusion of goodextrusion coatings. The crystals can act as a filler in the matrix, andso can mineralization, improving some mechanical properties. A totallyamorphous polyolefin would be grease-like and have poor physicalproperties. A totally crystalline polymer would be very hard andbrittle. High-density polyethylene (HDPE) resins have molecular chainswith comparatively few side chain branches. Therefore, the chains arepacked closely together. Polyethylene, polypropylene, and polyesters aresemi-crystalline. The result is crystallinity up to 95%. Low-densitypolyethylene (LDPE) resins have, generally, a crystallinity ranging from60% to 75%, and linear low-density polyethylene (LLDPE) resins havecrystallinity from 60% to 85%. Density ranges for extrusion coatingresins include LDPE resins that range from 0.915 g/cm³ to 0.925 g/cm³,LLDPE resins have densities ranging from 0.910 g/cm³ to 0.940 g/cm³, andmedium-density polyethylene (MDPE) resins have densities ranging from0.926 g/cm³ to 0.940 g/cm³. HDPE resins range from 0.941 g/cm³ to 0.955g/cm³. The density of PP resins range from 0.890 g/cm³ to 0.915 g/cm³.

Addition of a mineral filler to the polymer results in a rise inviscosity. The addition of filler may also change the amount ofcrystallinity in the polymer. As polymer crystals are impermeable to lowmolecular weight species, an increase in crystallinity also results inimproved barrier properties, through increased tortuosity. This effectis expected to be prevalent for fillers that induce a high degree oftranscrystallinity. Some minerals can change the crystallizationbehavior of some thermoplastics and thus the properties of the polymerphase are not those of virgin material, providing novel characteristicsduring processing and in the performance of the finished compositestructure. Thermoplastics crystallize in the cooling phase and solidify.Solidification for semi-crystalline polymers is largely due to theformation of crystals, creating stiffer regions surrounding theamorphous area of the polymer matrix. When used correctly, mineralfillers can act as nucleating agents, normally at higher temperatures.This process can provide mechanical properties in the polymer compositefavorable to high barrier performance and adhesion to fiber surfaceswithout a detrimental effect on heat sealing characteristics. Mineralscan begin to significantly affect crystallinity when used from about 15%to about 70% by weight of the polymer composite. Some of the factorsinfluencing mechanical adhesion to paper include extrudate temperature,oxidation, and penetration into the fibers. Mineral onset temperaturesof the polymer extrudate influence cooling rate upon die exit to the niproller, which can be adjusted by the extruder air gap setting. Other keyfactors include the mass of the polymers of the polymer interface layer.The crystalline onset temperatures vary, however, examples are shown inTable 4, below.

TABLE 4 Selected Polymers with Estimated Mineral Onset TemperaturesUnfilled Polypropylene 120-122° C. Calcium Carbonate 120-125° C.Dolomite 120-131° C. Talc 120-134° C. Silica 120-122° C. Mineral Fiber120-122° C. Mica 120-124° C.

Further, homogeneous blends of solid olefin polymers with varyingdensities and melt indexes can be mixed within the mineral compositelayer, either interspersed or non-interspersed through coextrusion. Themineral-containing composite layer can be applied and bondedsubstantially and continuously on at least a fiber-containing layerusing extrusion or extrusion lamination, including blown film, cast, orextrusion coating methods. Polymer content of the mineral-containinglayer can be used as a tie layer for interspersed and non-interspersedconstructions as well as particle bonding agents within each individuallayer. These bonding agents or tie layers can include individually, orin mixtures, polymers of monoolefins and diolefins, e.g. polypropylene,polyisobutylene, polybut-1-ene, poly-4-methylpent-1-ene,polyvinylcyclohexane, polyisoprene or polybutadiene, homogeneousmettallocene copolymers, and polymers of cycloolefins, e.g. cyclopenteneor norbornene, polyethylene, cross-linked polyethylene, ethylene oxideand high density polyethylene, medium molecular weight high densitypolyethylene, ultra heavy weight high density polyethylene, low densitypolyethylene, very low density polyethylene, ultra low densitypolytheylene; copolymers of monoloefins and diolefins with one anotheror with other vinyl monomers, e.g. ethylene/propylene copolymers, linearlow density polyethylene, and blends thereof with low densitypolyethylene, propylene but-1-ene, copolymers ethylene,propylene/isobutylene copolymers, ethylene/but-1-ene copolymers,ethylene/hexene copolymers, ethylene/octene copolymers,ethylene/methylepentene copolymers, ethylene/octene copolymers,ethylene/vinyelcyclohexane copolymers, ethylene/cycloolefin copolymers,COC, ethylene/1-olefin copolymers, the 1-olefin being produced in situ;propylene/butadiene copolymers, isobutylene/isoprene copolymers,ethylene/vinylcyclohexene copolymers, ethylene vinyl acetate copolymers,ethylene/alkyl methacrylate copolymers, ethylene/acrylic acid copolymersor ethyelene/acrylic acid copolymers and salts thereof (ionomers) andterapolymers of ethylene with propylene and diene, such as, for example,hexadiene, dicyclopentadiene or ethylidenenorbornene; homopolymers andcopolymers that may have any desired three dimensional structure(stereo-structure), such as, for example, syndiotactic, isotactic,hemiisotactic or atactic stereoblock polymers are also possible;polystyrene, poly methylstyrene, poly alph-methystyrene, aromatichomopolymers and copolymers derived from vinylaromatic monomers,including styrene, alpha-methylstyrene, all isomers of vinyltoluene, inparticular p-vinyletoluene, all isomers of ethylstyrene, propylstyrene,vinylbiphenyl, vinylnaphthalene and blends thereof, homopolymers andcopolymers of may have any desired three dimensional structure,including syndiotactic, isotatic, hemiisotactic or atactic, stereoblockpolymers; copolymer, including the above mentioned vinylaromaticmonomers and commoners selected from ethylene, propylene, dienes,nitriles, acids, maleic anhydrides, vinyl acetates and vinyl chloridesor acryloyl derivatives and mixtures thereof, for examplestyren/butadiene, styrene/acrylonitrile, styrene/ethylene(interpolymers) styrene/alkymethacrylate, styrene/butadiene/alkylacrylate, styrene/butadiene/alkyl methacrylate, styrene/maleicanhydride, styrene copolymers; hydrogen saturated aromatic polymersderived from by saturation of said polymers, includingpolycyclohexylethylene; polymers derived from alpha, beta-unsaturatedacids and derivatives; unstaturated monomers such asacrylonitrile/butadiene copolymers acrylate copolymers, halidecopolymers and amines from acyl derivatives or acetals; copolymers witholefins, homopolymers and copolymers of cyclic ethers; polyamides andcopolyamides derived from diamines and dicarboxylic acids and or fromaminocarboxylicacides and corresponding lactams; polyesters andpolyesters derived from dicarboxylic acids and diols and fromhydroxycarboxylic acids or the corresponding lactones; blockedcopolyetheresters derived from hydroxyl terminated polyethers;polyketones, polysulfones, polyethersufones, and polyetherketones;cross-linked polymers derived from aldehydes on the one hand phenols,ureas, and melamines such as phenol/formaldehyde resins and cross-linkedacrylic resins derived from substantial acrylates, e.g. epoxyacrylates,urethaneacrylates or polyesteracrylates and starch; polymers andcopolymers of such materials as poly lactic acids and its copolymers,cellulose, polyhdyroxy alcanoates, polycaprolactone, polybutylenesuccinate, polymers and copolymers of N-vinylpyrroolidone such aspolyvinylpyrrrolidone, and crosslinked polyvinylpyrrolidone, ethyl vinylalcohol. More examples of thermoplastic polymers suitable for themineral-containing composite include polypropylene, high densitypolyethylene combined with MS0825 Nanoreinforced POSS polypropylene,thermoplastic elastomers, thermoplastic vulcinates, polyvinylchloride,polylactic acid, virgin and recycled polyesters, cellulosics,polyamides, polycarbonate, polybutylene tereaphthylate, polyesterelastomers, thermoplastic polyurethane, cyclic olefin copolymer;biodegradable polymers such as Cereplast-Polylactic acid, Purac-LactidePLA, Nec Corp PLA, Mitsubishi Chemical Corp GS PLS resins, NatureworksLLC PLA, Cereplast-Biopropropylene, Spartech PLA Rejuven 8, resins madefrom starch, cellulose, polyhydroxy alcanoates, polycaprolactone,polybutylene succinate or combinations thereof, such as Ecoflex FBX 7011and Ecovio L Resins from BASF, polyvinylchloride and recycled andreclaimed polyester such as Nodax biodegradable polyester by P & G.

The mineral-containing layer can include coupling agents from about0.05% to about 15% of the weight of the mineral-containing layer. Theagents aid in the mixing and the filling of the mineral into the polymermatrix. Functional coupling groups include (Pyro-) phosphato, Benzenesulfonyl and ethylene diamino. These can be added to thermoplasticsincluding polyethylene, polypropylene, polyester, and ethyl vinylalcohol, aluminate, siloxane, silane, amino, malice anhydride, vinyl andmethtacryl. The results of these combinations improve adhesion tofibers, heat seal strength, heat seal activation temperatures, surfaceenergy, opacity, and cosmetics. Mineral content can include, but is notlimited to, wollanstonite, hydrated and non-hydrated, magnesiumsilicate, barium sulfate, barium ferrite, magnesium hydroxide, magnesiumcarbonate, aluminum trihydroxide, magnesium carbonate, aluminumtrihydroxide, natural silica or sand, cristobalite, diaonite,novaculite, quartz tripoli clay calcined, muscovite, nepheliner-syenite,feldspar, calcium suphate-gypsum, terra alba, selenite, cristobalite,domite, silton mica, hydratized aluminum silicates, coke,montmorillonite (MMT), attapulgite (AT) carbon black, pecan nut flour,cellulose particles, wood flour, fly ash, starch, TiO2 and otherpigments, barium carbonate, terra alba, selenite, nepheline-syenite,muscavite, pectolite, chrysotile, borates, sulfacates, nano-particles ofthe above from 0.01 to 0.25 micron particle size, and precipitated andground calcium carbonate. Among, but not limited, procedures generallyinvolving the use of polymerization initiators of catalysts for thepolymerization of butene-1 monomer to polymers of high molecular weight,preferably catalytic systems used in such procedures are the reactionproducts of metal alkyl compounds such as aluminum triethyl, and a heavymetal compound, such as the trihalides of Groups IV-VI metals of theperiodic table, e.g. titanium, vanadium, chromium, zirconium, molybdenumand tungsten. The formation of polymers exhibiting substantial isotacticproperties as wells as the variations in the molecular weight and thenature of the polymerization catalyst, co-reactants, and reactionconditions. Suitable, but not limited to, isotatic polybutylenes arerelatively rigid at normal temperatures but flow readily when heated,and they most preferably, should show good flow when heated, expressedin melt flow. Applicable isotatic polybutylenes should show a melt flowof from 0.1 to 500, preferably 0.2 to 300, more preferably from 0.4 to40, most preferably 1 to 4. Other polymers expressed within the contentsof the present specification should also be considered within theseparameters.

Regarding the mineral-containing composite layer, upon substantially andcontinuously bonding to the fiber-containing using extrusion coating orextrusion lamination techniques, the layer of which can then be used toform a laminated structure of which the mineral-containing layer can beused as a peel coat onto a desired backing material. The best peel seal,for example, to the mineral-containing layer of the composite, may beselected from poly-4-methyl pentene, nylon, high-density polyethylene(HDPE), aluminum foil, polycarbonate polystyrene, polyurethane,polyvinyl chloride, polyester, polyacrylonitrile, polypropylene (PP),and paper. An example extrusion process can be accomplished with a screwor pneumatic tube. Sometimes the mineralized polymers can be combinedwith such materials as plasticizers lubricants, stabilizers, andcolorants by means of Banbury mixers. The resulting mix is then extrudedthrough rod shaped dies and chipped into pellets. Pelletized mineralizedpolymer can then enhance the mineral and other content by “letting down”the resin pellet mix with inline or offline mixing capability beforebeing fed into the end of a, for example, screw-type extruder, heated,and mixed into a viscous fluid or semi-fluid in the extruder barrel forfurther processing to the die. Further, when properly dispersed theinteraction between the mineral particles and the polymer contentwithout covalent bonding, results in improved van der Waals forces thatprovide attraction between the materials. This interaction results insome adhesion in the composite during extrusion, resulting in anabsorbed polymer layer on the filler surface.

These considerations combined with the unique attributes of the mineralcontent dispersed within the polymeric matrix of both monolayer andmultilayer mineral composite layers impact the application of heat thatinitiates the melting of semi-crystalline polymers, causing the polymermolecules to better diffuse across the interface. Given sufficient time,the diffused polymers form entanglements at the inter-facial layer. Thiseffect is possible at extrusion line speeds from up to about 100 FPM andextrusion lamination up to about 3,500 FPM, using semi-crystallinemineralized resin blends with extrusion equipment die and barrel zonetemperatures from about 540 degrees to about 615 degrees F. Because ofimproved mineral thermal properties, oxidation of the extrudate uponexiting the die but before fiber contact improves from about 10-50%,thus greatly strengthening fiber bonding characteristics under normalequipment operating conditions.

Molecular weight ranges of the polymer bonding agent component of themineral-containing layer are from about Mw 10,000 to about Mw 100,000.Further, about 10%-70% of the polymer bonding agent may have a branchingindex (0 of about 0.99 or less as measured at the Z-average molecularweight (Mz) of the polymer. Some, part, or all of the mineral-containinglayer polymer bonding agent is preferred but not required to have anisotactic length of from about 1 to about 40. Further, the polymerbonding agent of the mineral-containing layer has a shear rate range offrom about 1 to about 10,000 at temperatures from about 180° C. to about410° C.

TABLE 5 Particle characteristics of CaCO₃ Particle Coating Fatty AcidsIncluding Stearates Hunter Reflectance (Green)  91-97% HunterReflectance (Blue)  89-96% Mohs Hardness 2.75-4.0  pH in Water, 5%Slurry, 23° C. 8.5-10.5 Resistance in Water, ohms, 23° C. 5,000-25,000ASTM D1199 Max % on 325 Mesh 0.05-0.5  Volume Resistivity @ 20° C.10⁹-10¹¹ ohms pH 8.5-10.5 Standard Heat of Formation, CaCO₃288.45-288.49 Kg-cal/mole from its Elements @ 25° C. Standard FreeEnergy of Formation, 269.53-269.78 Kg-cal/mole CaCO₃ from its ElementsSpecific Heat (between 0 to 100° C.) 0.200-0.214  Heat Conductivity0.0071 g · ca/sec · cm² · 1 cm thick @ 20° C. Coefficient of LinearExpansion C = 9 × 10⁻⁶ @ 25 to 100° C. C = 11.7 × 10 @ 25 to 100° C.

Also, nano-cellulose can be used in the mineral-containing compositelayer having a crystalline content from about 40%-70%, includingnano-fibrils, micro-fibrils, and nanofibril bundles, having lateraldimensions from about 0.4-30 nanometers (nm) to several microns, andhighly crystalline nano-whiskers from about 100 to 1000 nanometers.Nano-cellulose fiber widths are from about 3-5 nm and from about 5-15nm, having charge densities from about 0.5 meq/g to about 1.5 meq/g,with the nano-cellulose having a stiffness from about an order of140-220 GPa and tensile strength from about 400-600 MPa.

The mineral-containing interspersed or non-interspersed polymercomposite layer can be substantially and continuously directly bonded toa fiber surface or to the fiber surface interface adhesive layer usingextrusion coating or extrusion lamination. Further, the fiber-containinglayer can contain inorganic mineral coatings and fillers, e.g. clay,kaolin, CaCO₃, mica, silica, TiO₂ and other pigments, etc. Othermaterials found in the fiber-containing layer include vinyl andpolymeric fillers and surface treatments such as starch and latex.Preferred characteristics of the fiber-containing layer bound to themineral-containing layer include, but are not limited to, a smoothnessrange of about 150 to about 200 Bekk seconds, and an ash content fromabout 1% to about 40% by weight. Also, in this example, thefiber-containing layer coefficient of static friction, μ, is from about0.02 to about 0.50. Identified cellulose within the fiber-containinglayer preferably has a thermal conductivity from about 0.034 to about0.05 W/m·K. If using air-laid paper or non-woven fibers, the fibercontent is preferably from about 40% to about 65% of the layer byweight. Other preferred, but not limiting, characteristics of thefiber-containing layer are shown in Table 6, below.

TABLE 6 Fiber Layer Characteristics Fiber Aspect Ratio (Average)  5-100Fiber Thickness (Softwood) 1.5-30 mm Fiber Thickness (Hardwood) 0.5-30mm Filled Fiber Content 1% to 30% Fiber Density 0.3-0.7 g/cm² FiberDiameter 16-42 microns Fiber Coarseness 16-42 mg/100 m Fiber Pulp TypesMechanical, Thermo-Mechanical, Chemi- (Single- to Triple-Layered)Thermo-Mechanical, and Chemical Permeability 0.1-110 m² × 10¹⁵ HydrogenIon Concentration 4.5-10   Tear Strength (Tappi 496, 56-250 402) TearResistance (Tappi 414) m 49-250 Moisture Content 2%-18% by Weight

Coextrusion methods provide the possibility for non-interspersed contactlayers within the mineral-containing layer. Based on performance andstructural requirements, the finished composite structures can containseparate layers in the composite that can vary based on types of mineraland amount of mineral content per layer, degrees of amorphous andcrystalline content per layer, and type of polymer resin and resin mixesper layer. The more extruders feeding a common die assembly, the morelayered options become available to the non-interspersedmineral-containing layer. The number of extruders depends on the numberof different materials comprising the coextruded film. For example, anon-interspersed mineral-containing composite may comprise a three-layerto six-layer coextrusion including a barrier material core that couldbe, for example, a high density polyethylene and low densitypolyethylene mix having a 25% to 65% mineral content by weight in thefirst base layer, this layer making contact with the fiber surface.Subsequent layers may contain differing mineral contents, neat LDPE, orpolypropylene. Another example is a six-layer coextrusion including abottom layer of LDPE, a tie-layer resin, a 20% to 65% mineral-containingpolypropylene barrier resin, a tie-layer, and an EVA copolymer layer,and a final layer of polyester. Any mineral-containing barrier layeraccording to the present embodiments may have a basis weight from about4 lbs/3 msf to about 60 lbs/3 msf, a density from about 1.10 g/cm³ toabout 1.75 g/cm³, and/or a caliper from about 0.30 mil to about 3 mil.Tie-layers often are used in the coextrusion coating of multiple layerconstructions where mineral-containing polymers or other resins wouldnot bond otherwise, and tie-layers are applied between layers of thesematerials to enable desired adhesion. Another example multilayer filmconstruction is 25%-65% mineral content LLDPE/tie-layer/EVOHbarrier/tie-layer/EVA. Interspersed, e.g. monolayer, andnon-interspersed, e.g. multilayer, coextrusions can comprise from one tosix layers of the mineral-containing layer substantially andcontinuously bonded across the surface of a fiber-containing layer.Layers can be designed to improve hot tack, heat-sealability, sealactivation temperature, and extrudate adhesion to fiber, mineralenhancement of barrier performance, surface energy, hot and cold glueadhesion improvements, etc.

Table 7, below, shows example layer constructions (not limited to) foundin the mineral-containing resin and extrusion coated or laminatecomposite structure. The preferred single layer ranges contain fromabout 0% to about 65% by weight mineral content, from 25%-80% amorphousto 25%-80% crystalline structure by weight, and 25%-65% cellulose,nano-cellulose, or nano-minerals by weight. Also, the mineral content ofthe mineral-containing layer(s) may comprise different fillers withdifferent densities, size, and shape depending upon the desired outcomeof the final composite structure.

TABLE 7 Examples of Non-Interspersed (Multilayered) Mineral CompositeLayers Layer Structure Example 1 Example 2 Example 3 Example 4 Example 5Example 6 Monolayer (1) LDPE HDPE LDPE-HDPE resin LDPE-MMW LLDPE-LDPEPLA- bio blend HDPE resin resin blend derived starch blend based resinblend Monolayer (2) Bio-derived, LDPE-bio LDPE-LLDPE-bio LDPE-HDPE-PP-bio derived ULDPE-HDPE- starch polymer derived starch derived starchLLDPE- blend starch based bio derived blend polymer blend blend polymerblend starch polymer blend 3-Layer HDPE-LDPE HDPE-PP HDPE-PET LDPE-PPLLDPE-PET EVA-LDPE 4-Layer EVA-ethylene HDPE-EVA- Biaxially orientedOriented EVA-PE- PVC-ABS- vinyl acetate Ionomer resin-homopolypropylene- polypropylene- MMWHDPE- PC Nylon EEA-ethylenePolyamides- polyester- HDPE-PE- oriented acrylic acid- polypropylene-PEmetallized PET polypropylene HDPE-EAA ethylene acrylic acid

Additionally, if relative clarity is desired in the mineral-containingcomposite layer the following resins are possible, but not limiting,bonding agents for these materials: carboxy-polymethyelene, polyacrylicacid polymers and copolymers, hydroxypropylcellulose, cellulose ethers,salts for poly(methyl vinyl ether-co-maleic anhydride), amorphous nylon,polyvinylchrloride, polymethylpentene, methylmethacrylate-acrylonitrile-butadiene-styrene, acrylonitrile-styrene,poly carbonate, polystyrene, poly methylcrylate, polyvynl pyrrolidone,ply (vinylpyrrolidone-co-vinyl acetate), polyesters, parylene,polyethylene napphatalate, ethylene vinyl alcohol, and polylactic acidscontaining from about 10% to about 65% mineral content. Variousmineral-containing layer polymer and mineral content can be determinedbased upon performance and content requirements considering theparameters shown in Table 7, above. Branched, highly branched, andlinear polymer combinations are possible in all composite layerconstructions. Examples are shown in Table 7 (not limited tocombinations within the table) of the interspersed and non-interspersedmineral-containing layer constructions, not including tie layers. Layercombinations depend on coextrusion die design, flow properties, andprocessing temperature, allowing for coextrusion fusion layers and/orsubsequently extrusion laminating or laminating the layers into thefinal mineral-containing composition, of which individual(non-interspersed) or total combination of layers have by weight mineralcontent of about 20%-65%. Layers can be uniaxially or biaxially oriented(including stretching) from about 1.2 times to about 7 times in themachine direction (MD) and from about 5 times to about 10 times in thecross-machine (transverse) direction (CD), and stretched from about 10%to about 75% in both the MD and CD directions. Generally, althoughwithout limitation, polyolefin mineral content bonding agents havenumber average molecular weight distributions (Mn) of from about 5,500to about 13,000, weight average molecular weight (Mw) of from about170,000 to about 490,000, and Z average molecular weight (Mz) of fromabout 170,000 to about 450,000. A coextruded mineral-containing layermay differ in molecular weight, density, melt index, and/orpolydispersity index within the finished layer structure. Thepolydispersity index is the weight average molecular weight (Mw) dividedby the number average molecular weight (Mn). For example only, andwithout limitation, the mineral-containing layer may have a Mw/Mn ratioof from about 6.50 to about 9.50. Using wet or dry ground CaCO₃ as anexample, it can be surface treated at levels from about 1.6 to about 3.5mg surface agent/m² of CaCO₃. The surface treatment can be appliedbefore, during, or after grinding. Mean particle sizes range from,without limitation, about 0.7 microns to about 2.5 microns, having a topcut from about d98 of 4-15 microns, and a surface area of from about 3.3m²/g to about 10.0 m²/g. For improved dispersion into the polyolefinbonding agent, the CaCO₃ mineral content can be coated with fatty acidsfrom between, without limitation, about 8 to about 24 carbon atoms.

The preferred surface treatment range is about 0.6% to about 1.5% byweight of treatment agent or about 90%-99% by weight of CaCO₃.Polyolefin bonding agents having lower molecular weights and high meltindex provide improved downstream moisture barrier characteristics.Preferred mineral layer content could include finely divided wet groundmarble with 65% solids in the presence of a sodium polyacrylatedispersant, dried, and surface treated, and also dispersant at 20%solids, dried, and surface treated.

Testing methods for measuring moisture vapor transmission rates andwater vapor transmission rates (MVTR/WVTR) often involve tropicalconditions (100° F. and 90% RH) according to TAPPI Test Method T-464,orienting the barrier coating toward the higher humidity of the chamberatmosphere, when it is present on the surface. For water resistance, thestandard short (2 minute) and long (20 minute) Cobb test is often used.For oil, two tests are commonly used. The first is the 3M kit test perTAPPI T-559 standards, coating film weight as measured by TAPPI 410standards. The second is red dyed canola oil and castor oil exposure tothe coating surface using a 2-minute and a 20-minute Cobb ring.

Extruded mineral-containing interspersed and non-interspersed compositelayers of the present embodiments demonstrate high barrier performancecharacteristics when substantially and continuously bonded tofiber-containing layers. The fiber-containing layers may include intheir composition or surface, but are not limited to, mineral andpolymeric sizings, surface treatments, coatings, and mineral fillers.Some advantages of the non-fiber content of the fiber-containing layerinclude improved fiber layer printability, ink hold out, dynamic waterabsorption, water resistance, sheet gloss, whiteness, delta gloss, pickstrength, and surface smoothness. Often, mineral content containedwithin or upon one or more opposing surfaces of the fiber-containinglayer can include, but is not limited to, clay, calcined clay, orcombinations thereof. The minerals are frequently applied to the surfaceof the fiber-containing layer through a blade or air coating process.Common mineral binding methods include the use of protein systems suchas a mixture of vinyl acrylic/protein co-binders. Another non-limitingexample is tri-binder systems, e.g. SB/Pvac/Protein. Further, pigmentssuch as TiO₂ can be included to improve whiteness characteristics. Thenature of the fiber layer's mineral and binder content can impact theselection of the non-interspersed and interspersed mineral-containinglayer characteristics when bonded substantially and continuously to oneor more sides of the fiber-containing layer(s), which comprise part ofthe composite structure. Examples of non-fiber content in thefiber-containing layer include, but are not limited to, 50%-95% of #1clay or #1 fine clay, 3%-20% by part calcined clay, 3%-40% by part TiO₂,2%-45% vinyl acrylic, and from about 1% to about 35% protein binders,co-binders, or tri-binders.

Also, the fiber-containing layer surfaces can have from about 55% toabout 88% TAPPI 452 surface brightness. The examples shown in Table 8,below, illustrate acceptable, but not limiting, fiber-containing layercharacteristics for substantially and continuously bonding to themineral-containing layer. Surface roughness values are based upon ParkerPrint Surf (μm) and Bendtsen (mls/min) per TAPPI T-479 (moderatepressure), TAPPI T-538, and TAPPI 555 (print-surf method). Tearresistance per TAPPI T-414 standards are expressed in millinewtons (mN).Surface brightness is expressed per TAPPI 452. Burst strength isexpressed per TAPPI 403 standards. Bursting strength is reported asburst ratio=bursting strength (lbs/in²)/basis weight (lbs/ream).Internal bond strength or interlayer strength of the fiber-containinglayer is an important characteristic as represented by TAPPI T-403 andT-569. Preferred fiber-containing layer internal strengths are, but arenot limited to, from about 125 J/m² to about 1150 J/m². Further,fiber-containing layer Z-direction tensile strength per TAPPI T-541testing standard is from about 45-50 Nm/g to about 950 Nm/g. Finally,preferred, but non-limiting, fiber-containing layer air resistance perTAPPI 547 is from about 0 to about 1500 mls/min, as represented by theBendsten method.

TABLE 8 Fiber-Containing Layer Characteristics Tear Burst Fiber WeightResistance Strength (lbs/3 msf) g/m² (Mn) Surface Roughness (kPa) 40-75 60-110 400-700 2.0-5.5 μm 140-300 >75 110-130 650-750 2.0-3.5 μm175-400 >115 180-190 1400-1900 100-2500 mls/min 175-475 >130 205-2151600-2200 100-2500 mls/min 250-675 >200 315-330 1900-3200 100-2500mls/min 500-950 >300 460-195  500-4000 100-2500 mls/min  700-1850

Table 9, below, displays finished composite board barrier performanceranges, but is not limited to, that of a composite structure having fromabout 20% to about 70% mineral-containing layer bonded to at least oneside of a fiber-containing layer. The mineral-containing layer can beeither a dispersed monolayer or non-interspersed coextrusion, forexample.

TABLE 9 Barrier Values of Formed Composite Structure Test Method TAPPIT441 TAPPI T464 TAPPI T410 Tappi T559 Test Name WVTR in Cobb WaterAbsorption Tropical Conditions Mineral layer Wgt Grease Resistance Unitsg/m² 3M Kit Test# Sample 2 minute 30 minute Coated Uncoated # FiberLayer Cobb Cobb g/m² g/100 in² g/m² lb/1000 ft² Side Side 1 RecycledFiber .28 mil caliper 0.22 — 23.4 1.51 *12  **1−  2 Virgin Fiber .20 milcaliper 0.40 0.00 15.2 0.98 32.3 4.12 12 1− 3 Recycled Fiber .20 milcaliper 0.00 — 18.6 1.20 3.45 12 1− 4 85-100% Recycled Fiber .20 milcaliper 0.10 0.05 13.9 0.89 18.25 3.55 12 1− 5 Virgin-TMP content .30mil caliper — — 7.58 0.49 12 1− 6 Clay coated 1 side- .18 mil caliper —0.45 7.13 0.46 7.5 12 1− bleached 7 Fiber 2-side bleached .18 milcaliper 0.00 — 9.31 0.60 6.44 12 1− 8 Fiber 1 side, bleached .18 milcaliper 0.50 0.11 37.7 2.43 11.33 12 1− 9 Virgin Kraft- clay coated .16mil caliper 0.05 0.11 15.0 0.97 3.94 12 1− 10 Virgin Kraft- clay coated.14 mil thick 0.00 0.10 14.1 0.91 28.1 3.89 12 1− 11 Clay coatedunbleached .18 mil caliper 0.00 0.05 13.0 0.84 6.2 12 1− kraft-100%virging 12 Solid Unbleached Sulfate .18 mil caliper 0.00 0.00 9.49 0.6152.2 5.5 12 1− Note: 1 mil = 1/1000th of an inch

Table 10, below, shows the barrier performance of a formed compositehaving a monolayer HDPE-PE mix with a density from about 0.925 gm/cm³ toabout 0.960 g/cm³ and containing from about 36% to about 45% mineralcontent by weight.

TABLE 10 Barrier Values of a Formed Composite Structure, Interspersed(Mono), Mineral-Containing Layer Monolayer 40%-60% Mineral Content(HDPE-PE MIX) WVTR in Cobb Water Tropical Conditions Mineral Absorption100° F./90% R.H. layer weight Unit Fiber type g/m² g/100 lb/1000 Sample2-min 30-min g/m² in² g/m² ft² Recycled 0.2 0.1 16.7 1.08 24.9 5.09Recycled 0.0 0.0 9.7 0.63 49.6 7.4 Virgin Kraft 0.0 0.1 11.1 0.72 32.86.73 Virgin Kraft 0.1 0.1 9.9 0.64 36.9 7.57 Virgin Kraft 0.0 0.1 8.70.56 36.2 7.42 Virgin Kraft 0.0 0.2 7.8 0.50 41.0 6.46 Virgin Kraft — —— — 26.1 5.35

Table 11, below, shows projected moisture barrier performance (MVTR,WVTR) for the present embodiments, comparing a coextrudedmineral-containing layer bonded to a surface of a fiber-containinglayer, the mineral-containing layer having both a monolayer and amultilayer (coextrusion) construction. The fiber-containing layer inTable 11 lists Klabin virgin kraft fiber. However, the data isapplicable to a range of both virgin and recycled fiber surfaces toinclude similar various weights and densities known in the art. MaximumMVTR via coextrusion is projected to be about the values in Table 11 inmineral-containing layers down to about 12 g/m² layer weight. The dataillustrates two different MVTR values. The first value is coextrusion.Coextrusion can provide superior results because of the flexibility toalter the type of polymers used per layer, density, branched or linearmolecular nature, as well as crystallinity, among others. Also, becauseof stress fracturing found in more monolayer constructions as a resultof bending, scoring, and processing, performance improvements usingcoextrusion are possible. The base layer in the coextrusion can be moredense and crystalline, for example, than the outer layer, which is moreamorphous and light density and more linear, thus not as vulnerable tostress fracture within the matrix, preventing percolation through thelayer. Other options for improving processing include additives to themineral-containing blend, which include, but are not limited to,elastomers.

TABLE 11 Barrier Attributes of Mineral-Containing Layer Bonded toFiber-Containing Layer Based for Interspersed (Monolayer) andNon-Interspersed (Coextruded) Composite Flat Samples Full Case MineralLayer Project Barrier Peformance Table Fiber Layer − Outer layer PreScore + Bed Post Score Weight Ethylene Co-Polymer Ranges WVTR-TropicalWVTR Mineral Layer Density--------------- % Amorphous Uncoated Mineralgm/m2 gm/m2 WVTR Range Box board 38-65% day Variation day VariationRanges 1.22-1.41 g/cm3 25%-65% 20 pt. Klabin 2+ layer coex 5 to 13 0.2011 to 17 0.2 15 gsm 50 gsm 1.22-1.36 g/cm3  25-70% 20 pt. KlabinMonolayer 8 to 22 0.2 14 to 25 0.2 15 gsm 50 gsm

FIG. 1 is a schematic side cross-sectional view of a multilayerrepulpable packaging composite material 20 according to the presentembodiments. The illustrated embodiment includes a mineral-containinglayer 22 having an outer or heat-sealable surface 24. FIG. 1A is adetail view of the portion of FIG. 1 indicated by the circle 1A-1A. Asshown in FIG. 1A, a plurality of mineral particles 26 are interspersedwithin a bonding agent 28, which may be a thermoplastic. With referenceto FIG. 1, the mineral-containing layer 22 may be substantially andcontinuously bonded to a first surface 30 of a fiber-containing layer32. Another mineral-containing layer 22 may be substantially andcontinuously bonded to a second surface 34 of the fiber-containing layer32, the second surface 34 being opposite the first surface 30. Withreference to FIG. 1A, the fiber-containing layer 32 includes a pluralityof fiber particles 36 interspersed within a bonding agent 38, which maybe a thermoplastic. The thermoplastic bonding agent of either or both ofthe mineral-containing layer 22 and the fiber-containing layer 32 maycomprise, for example and without limitation, polyolefin, polyester, orany other thermoplastic or polymer-containing resins.

The mineral-containing layer(s) 22 may include about 30% to about 65%minerals, and the minerals may comprise any of the minerals describedthroughout this specification and combinations thereof. Themineral-containing layer(s) 22 may be adhered to the fiber-containinglayer 32 through coextrusion, extrusion-lamination, or any othersuitable method or process. Extrusion-lamination may comprise aseparately applied adhesive between the mineral- and fiber-containinglayers. The composite material 20 illustrated in FIG. 1 mayadvantageously be used as a single or multiple corrugate liner(s) ormedium(s) within a single-layered or multilayered corrugated structure.

FIG. 2 is a schematic side cross-sectional view of another multilayerrepulpable packaging composite material 40 according to the presentembodiments. The illustrated embodiment includes a mineral-containinglayer 22 substantially and continuously bonded to the first surface 30of a fiber-containing layer 32. In contrast to the embodiment of FIG. 1,in the embodiment of FIG. 2 the second surface 34 of thefiber-containing layer 32 is not bonded to a mineral-containing layer22.

FIG. 3 is a schematic side cross-sectional view of a repulpablemineral-containing material according to the present embodiments. Theillustrated embodiment includes a mineral-containing layer 22 havingboth the first and second surfaces 30, 34 uncovered by amineral-containing layer 22.

FIG. 4 is a schematic detail view of a pellet 42 of a mineral-containingresin with mineral particles interspersed within a bonding agent,according to the present embodiments. Pellets such as that illustratedin FIG. 4 may be used in an extrusion process to adhere themineral-containing layer 22 and the fiber-containing layer 32 to oneanother. With reference to FIG. 4, the mineral particles 26 areinterspersed within the bonding agent 28 within the pellet 42.

FIG. 5 is a schematic side cross-sectional view of another multilayerrepulpable packaging composite material according to the presentembodiments. The illustrated embodiment includes a firstmineral-containing layer 22 substantially and continuously bonded to thefirst surface 30 of a fiber-containing layer 32. A secondmineral-containing layer 44 is substantially and continuously bonded tothe second surface 34 of the fiber-containing layer 32. The secondmineral-containing layer 44 comprises three layers or plies of the firstmineral-containing layer 22. The first and second mineral-containinglayers 22, 44 may be secured to the fiber-containing layer 32 throughany of the processes described herein, such as coextrusion,extrusion-lamination, etc., or through any other process. The plies 22of the second mineral-containing layer 44 may be secured to one anotherthrough any of the processes described herein, such as coextrusion,extrusion-lamination, etc., or through any other process. One or more ofthe plies 22 may comprise a mineral content and/or a bonding agent thatis different from the mineral content and/or the bonding agent ofanother one or more of the plies 22. Further, the illustrated embodimentin which the second mineral-containing layer 44 comprises three layersor plies 22 is only one example. In other embodiments the secondmineral-containing layer 44 may have any number of layers or plies 22,such as two layers or plies, four layers or plies, five layers or plies,etc. In yet further embodiments, the fiber-containing layer 32 may havea multilayer mineral-containing layer 44 adhered to both the first andsecond surfaces 30, 32.

FIG. 6 is a schematic side cross-sectional view of another multilayerrepulpable packaging composite material 46 according to the presentembodiments. The material 46 of FIG. 6 includes multiple layers of anyof the material layers described herein, such as a first dual layer 48and a second dual layer 50 with a corrugated layer 52 therebetween.

The composite materials illustrated in the foregoing figures anddescribed above are well-suited for use as packaging materials, such asfor packages for containing one or more products. For example, andwithout limitation, such packages may comprise folding cartons and/orboxes. The package material has high performance heat sealcharacteristics, elevated barrier performance, is repulpable, andprovides excellent cosmetics and favorable economics. The presentcomposite materials can also be used as components, or layers, ofmultilayer packaging structures, such as corrugated boxes, and/or beused as a single-layer or multilayer corrugated liner or medium.

Example 1

To form a repulpable composite, a 38.5% by weight mineralized HPDE-PEresin containing additives was compounded using wet ground and coatedfor dispersion finely ground within a range of about approximately 5-14micron mean particle sized limestone-originating CaCO₃ particles withincremental crystalline silica content within a range of from about 0.2%to about 3.5%. The specific heat of the ground CaCO₃ particles was fromabout 0.19 to about 0.31 kcal/kg·° C. The HDPE had a density within arange of about 0.939 to about 0.957 g/cm³ and the PE had a density offrom about 0.916 g/cm³ to about 0.932 g/cm³. The HDPE-PE bonding agenthad a melt flow index of 14 g/10 minutes. The finished and pelletizedmineralized compound had an approximate density within a range of aboutof 0.125 to about 1.41 g/cm³. The compound was coextruded using themineralized HDPE-PE composite layer as a base layer applied at 22 g/m²coating thickness contacting the uncoated side of 320 g/m² weight Klabinvirgin paper surface having a TAPPI T-441 Sheffield Smoothness of 74, a7.5% moisture content, and a TAPPI T 556 MD-CD Taber Stiffness of 39.9and 17.4, respectively. The minor layer, or top facing, outer, polymerbonding agent mineral-containing layer of the coextrusion was about 8g/m² weight having a mineral content from about 4% to about 65%, thebase layer being predominately crystalline using the top layer toprovide additional moisture barrier at box bend, scoring, and foldingjoints. The extrusion processing condition melt temperature for the baselayer was within a range of approximately 560° F. to 610° F. with barreltemperatures from zone one to zone six from about 405° F. to 600° F.Base layer die temperature zones were approximately 575° F. to 600° F.The extruder die gap setting was within the range of 0.025″-0.046″.Unfilled Westlake® brand top neat PE mineral-containing layer processingwas consistent with neat LDPE. The extruder air gap was approximately4″-10″, providing sufficient base layer oxidation and excellent adhesionuse gas pre-heat, but without ozone or primer layers. The extrusion linespeeds were within the range of 150-600 meters per minute across a fiberweb with within 50″-118″ range. Post corona treatment was used. Rollstock was in-process quality control checked for adhesion using “tape”testing and saturated for pin holing. Coat weight testing was doneconsistently using lab instrumentation. Finished and coated roll stockwas rewound and sent for converting. Successful converting and packagingarticle forming, e.g. folding cartons/boxes, were done up to eightmonths post-extrusion coating. Using room temperature adhesives duringconverting, the roll stock was run on high speed detergent boxproduction lines at speeds from about 100 to 500 cartons per minute. Theenclosed detergent, being sensitive to moisture exposure, was shipped intropical moisture conditions. Glue seams and small, medium, and largecarton sizes were successfully formed having sufficient fiber tear,meeting standards with both room temperature and hot melt adhesives,including the manufacturer's seam. Moisture barrier testing wascompleted for large size sampling sizes, which included full convertedand formed case samples having MVTR performance of 13.91 g/m²/24 hourswith a minimum of 13.03 g/m²/24 hours, with a standard deviation of0.86. These results compared to 40 g/m² inline primed and then appliedaqueous PVDC coatings on the same Klabin board having an average MVTR of18.92 g/m²/24 hrs with a minimum of 16.83 g/m²/24 hours, a maximum of20.89 g/m²/24 hrs, with a standard deviation of 2.00, and also comparedto 20 micron thick BOPP primed and roll-to-roll laminated on the sameKlabin board having an average MVTR of 15.03 g/m²/24 hrs with a minimumof 13.20 g/m²/24 hrs, a maximum of 16.64 g/m²/24 hrs, with a standarddeviation of 1.41.

Example 2

To form a repulpable and recyclable composite, a 43.5% by weightmineralized PE resin containing additives was compounded using wetground and coated with fatty acid-containing materials for dispersionand finely ground approximately 4-12 micron mean particle sizedlimestone-originating CaCO₃ particles with incremental crystallinesilica content of less than from about 0.2% to about 5%. The resin blendalso had 5% by weight titanium dioxide (TiO₂) for a total mineralcontent of from about 48.5% by weight. The specific heat of the groundCaCO₃ particles was 0.21 kcal/kg·° C. The PE had a density of 0.919g/cm³ to about 93.1 g/cm³. The PE bonding agent had a melt flow index of16 g/10 minutes. The finished and pelletized mineralized compound had anapproximate density of 1.38 g/cm³. The compound was then extruded usingthe mineralized PE and TiO₂ composite layer as a mono layer applied at32 lbs/3 msf coating weight contacting the uncoated side of Rock TennAngelCote® approximately 100% recycled fiberboard with a nominal basisweight of 78 lbs/msf, with the paper surface having a TAPPI T-441Sheffield Smoothness of approximately 68-72, a 5% to 7.5% moisturecontent, and a TAPPI T 556 MD-CD Taber Stiffness g-cm of 320 and 105,respectively. The extrusion processing condition melt temperature wasapproximately 585° F. with barrel temperatures from zone one to zone sixfrom about 400° F. to about 585° F. Die temperature zones wereapproximately 575° F. to 585° F. The extruder die gap setting was withinthe range of 0.025″-0.030″. The extruder air gap was approximately6″-10″, providing excellent extrudate to fiber adhesion without a gaspre-heat, ozone, or primer layers. Extrusion line speeds were within therange of 150-1400 feet per minute across a 80″-118″ web width. Postcorona treatment was used. Roll stock was in-process quality controlchecked for adhesion using “tape” testing and saturated for visual pinholing. Post production coat weight testing was done consistently usinglab instrumentation. Finished and coated roll stock was rewound and sentfor converting. Successful converting and packaging forming was done upto three months post-extrusion coating. During converting, the rollstock was run for use in high barrier MVR requirement frozen seafood boxproduction lines at speeds up to 250 boxes per minute. The finishedcomposite material was formed, bent, scored, and machined at standardproduction rates. The mineral-containing surface layer was efficientlyoffset printed using standard industry inks and aqueous press coatings.The mineral coating layer was highly opaque and improved the brightnessof the base paper surface from about 59 bright to about 76 bright. Themineral layer had a resident dyne level range of 44-48 as measuredduring post-production testing. Moisture barrier testing was completedfor large size sampling sizes, which included full converted and formedcase samples having MVTR performance of 12 to 16 g/m²/24 hrs @ 100%humidity in tropical conditions with mineral composite layer coatweights from 12 lbs/3 msf to 16 lbs/3 msf.

Example 3

Example 3 illustrates three different finished repulpable compositescontaining bleached virgin board SBS paper within a caliper range fromabout 0.014″ to about 0.028″ having a mineral-containing layerextrusion-coated to the fiber-containing layer. These composites wereanalyzed for ash content with Tappi standard T211, and for repulpabilityusing an in-house procedure developed by the Georgia Institute ofTechnology. Results indicated that ash content varied from about 2.21%up to about 21.44%. Screen yield and overall recovery seem to depend atleast in part on ash content of the starting paper. A 40% by weightmineralized PE resin and a 47% by weight mineralized PE resin, bothcontaining additives, were compounded using wet ground and coated fordispersion finely ground approximately 5.0 to 13.0 micron mean particlesized limestone-originating CaCO₃ particles with incremental crystallinesilica content of less that about 5% by weight. The specific heat of theground CaCO₃ particles was 0.21 kcal/kg·° C. The PE had a density fromabout 0.919 g/cm³ to about 93.2 g/cm³. The PE bonding agent had a meltflow index of 16 g/10 minutes. The finished and pelletized mineralizedcompound had an approximate density from about 1.34 g/cm³ to about 1.41g/cm³. The compound was then extruded as a mono layer substantially andcontinuously applied on the fiber-containing layer at from about 7.5lbs/3 msf to about 16 lbs/3 msf layer weight contacting the uncoatedside of International Paper Fortress SBS and Clearwater Paper CandesceSBS having approximately 89% to approximately 100% bleached virginfiberboard with nominal basis weight from about 182 lbs to about 233lbs, with the paper surface having a TAPPI T-441 Sheffield Smoothness ofapproximately 68-72, a 5% to 7.5% moisture content, and a TAPPI T 556MD-CD Taber Stiffness g-cm above 375 and 105, respectively. Theextrusion processing condition melt temperature was from about 565° F.to about 610° F., with barrel temperatures from zone one to zone sixfrom about 400° F. to about 605° F. The die temperature zones wereapproximately 575° F. to 610° F. The extruder die gap setting was withinthe range of about 0.020″-0.040″. The extruder air gap was approximately4″-16″, providing excellent extrudate to fiber adhesion without a gaspre-heat, ozone, or primer layers. The extrusion line speeds were withinthe range of 150-1600 feet per minute across a 55″-118″ web width. Postcorona treatment was used. Roll stock was in-process quality controlchecked for adhesion using “tape” testing and saturated for visual pinholing. Post production coat weight testing was done consistently usinglab instrumentation. Finished and coated roll stock was rewound and sentfor converting. Successful converting and packaging forming was done upto three months post-extrusion coating. During converting, the rollstock was run for use in high barrier MVR requirement frozen seafood boxproduction lines at speeds up to 250-500 boxes per minute, and cupstockas well as ice cream packaging material converted from about 150 toabout 600 formed units per minute. The finished composite material wasformed, bent, scored, and machined at standard production rates. Themineral-containing surface layer was efficiently offset printed usingstandard industry inks and aqueous press coatings. The mineral coatinglayer was highly opaque and maintained the fiber layer brightness of thebase paper surface from about 80 to about 90 bright. The mineral layerhad a post corona treatment resident dyne level range of 42-56 asmeasured during post-production testing. Moisture barrier testing wascompleted for large size sampling sizes, which included full convertedand formed case samples having MVTR performance of about 8 g/m²/24 hrsto about 16 g/m²/24 hrs @ 100% humidity in tropical conditions withmineral composite layer coat weights from about 7.5 lbs/3 ms to about 16lbs/3 msf. Packages were closed and sealed using standard heat sealprocedures found on cup forming and folding carton production lines.

Example 4

Repulpability Experiment

1. Ash Content

Ash content was measured following Tappi standard T413. The time atmaximum temperature was extended to eight hours to ensure complete ash.

TABLE 12 Ash/Solids Content for Six Paper Samples Ash/Solids ContentSample Dish, g Sample Wt., g Solids, % Ash Content, % 1# 27.7401 1.144695.83 21.41 Duplicate 15.8099 1.1136 96.20 21.46 Average 96.02 21.44 2#18.8742 1.0837 96.16 5.41 Duplicate 16.1962 0.9697 96.11 6.45 Average96.14 5.93 3# 15.7174 1.0131 95.92 2.17 Duplicate 16.5933 1.0285 95.732.26 Average 95.83 2.21 4# 17.9733 0.9974 96.09 9.31 Duplicate 18.48391.0778 95.75 9.32 Average 95.92 9.32 5# 16.3182 1.0548 95.92 4.11Duplicate 18.3800 1.2260 96.28 3.83 Average 96.10 3.97 6# 28.1106 1.377294.88 2.80 Duplicate 27.5611 1.5707 95.24 2.76 Average 95.06 2.78

The above results indicate that the ash content of sample 1 # is 21.44%,the highest among the six samples, whereas that of sample 3 # is only2.21%. It is contemplated that the values shown in Table 12 above mayvary by about ±50%.

2. Repulpability

Around 25 g of oven dried paper samples were torn into 1″×1″ pieces andweighted into a preheated (around 52° C.) Waring blender, which wasequipped with a special blade to reduce fiber cutting. After 1,500 ml ofhot (around 52° C.) water was added, the paper was disintegrated on lowspeed (15,000 rpm) for 4 minutes. The content was then transferredquantitatively into a British disintegrator using 500 ml hot water asrinsing liquor, so that the pulp slurry had a temperature around 52° C.The pulp suspension was then de-flaked for 5 minutes with a Britishdisintegrator at 3,000 rpm. The disintegrated pulp was screened by usinga Valley flat screen with 0.01″ slot openings for 20 minutes. During thescreening, a water head over the screen was maintained at 3″ and waterflow was kept constant. Accepts and rejects were collected and were usedto calculate the screen yield (accepts/starting paper*100) and overallrecovery ((accepts+rejects)/starting paper*100). Images of the acceptsand rejects were taken to examine the fibers and flakes. After fullcompletion of the repulpability cycle, the entire procedure wascompleted without using an acid wash to clean the flat screen during thetest or dismantling the pressure screens to clean them before completingthe test. Also, there was no visible deposition on any part or thedisintegrator during the test.

TABLE 13 Repulpability Data of the Paper Samples Start Screen OverallSample Pulp, g Accepts, g Rejects, g Yield, % Recovery, % #2 26.44820.511 1.754 77.55 84.18 #3 25.203 19.421 1.963 77.06 84.85 #5 26.23520.700 2.044 78.90 86.69

The samples were disintegrated for 70,000 revolutions. It iscontemplated that the values shown in Table 13 above may vary by about±50%.

3. Determination of Fibers, Plastics, and Ash Compositions—DeterminedAsh Content of the Fraction Following the Procedure Stated in 1 (above)

Around 0.2 g was weighted into a 50 plastic vial. After 1.8 ml of 72%sulfuric acid was added, the content was mixed thoroughly and the samplemass turned to a paste. The vial was then set in a 30° C. heating blockfor 1 hour, and the content was stirred periodically. By the end of theheating treatment, water was added to the vial until a total of 50 mlvolume was reached. The vial was capped and set in a 121° C. autoclavefor two hours. This would completely hydrolyze the carbohydratecomponents and solubilize the acid soluble inorganics. By the end ofhydrolysis, the acid insoluble substances were collected over a tarredglass filter, which was preheated at 550° C. overnight. The collectedsubstances were plastics plus acid insoluble inorganics (ash), which wasdetermined by the procedure stated under heading 1 above. Thus, thefiber content was calculated from the weight difference of startingmaterials and substances after hydrolysis minus the acid solubleinorganics. This portion of inorganics was determined from the ashcontent stated under heading 3 above, minus acid insoluble inorganics.The plastics were the weight difference of acid insoluble substancesminus acid insoluble inorganics.

Validation—In validation run, 1.5 g starting materials was firsthydrolyzed with 15 ml of 72% sulfuric acid at room temperature for 1hour followed by a 3% sulfuric acid hydrolysis for 4 hours at boilingtemperature.

4. Stickies Analysis

Around 0.3 g materials were hydrolyzed following the procedure statedunder heading 3 above. The hydrolyzed content was filtered through blackfiltering paper (15 cm diameter). The retained white residues werethoroughly washed with water until neutral. When the filter paper wasdry, the residues on the black filtering paper were scanned with a HPscanner. A known dimension shape was placed in the scanner as areference. The image thus acquired was input to Image-J software. Setthreshold at 125/255 and scale based on the insert reference. Theparticles were analyzed and the output was input into MS Excel forfurther calculations. The stickies content was expressed as specifiedstickies area, which was defined as total stickies area in mm²/weight ofstarting materials in g.

5. Fate of Rosin Acids

Proper amount of mass from each fraction was weighted into 15 ml vials.After 10 ml DCM and 3 drops of 2 M HCL were added, the vial was firmlycapped with Teflon-lined caps, and shaken for 3 minutes. The vial wasset in room temperature overnight. 1 ml extract was filtered through alayer of sodium sulfate, and 100 μl clear filtrate was measured into a 1ml GC vial. After the content was dried under a stream of nitrogen, theresidues were derivatized with MSTFA (N-Methyl-N-(trimethylsilyl)trifluoroacetamide) at 50° C. for 30 minutes with periodic shaking. 1 μlderivatized mixture was injected into the GC/MS for analysis. The GC wasequipped with 60 meter SPB DB-5 fused silica capillary column and heliumwas used as carrying gas. GC operation conditions were set as follows:initial temperature 120° C., initial time 5 min., rate 15° C./min.,final temperature 315° C., and final time 30 minutes, inject porttemperature 250° C. The components were analyzed using an HP 5975C massdetector in EI mode. The operation parameters were properly set torealize maximum detection limit. Identification of individual compoundsbased on the commercial mass spectra libraries and in-house libraries.Peak area was used to anticipate the total mass of rosin acids.

6. Starch Detection

Around 0.2 g materials were weighted into a 10 ml vial. After 5 ml waterwas added, the vial was capped and placed in a 105° C. oven overnight.Around 2 ml water extract was transferred to a test tube and added with2 drops of 0.1 M iodine solution. If the solution inside the test tubeturned to blue, it indicated that starch was present.

Results

1. Repulpability

Coated paper board and product are repulped and recovered in threefractions: accepts, rejects, and wash-out. The oven dry weight of eachfraction, along with the accepts yield and overall yield, are listed inTable 14, below.

TABLE 14 Repulpability Data of the Paper Samples Repulpability StartWash- Accepts Overall pulp, Accepts, Rejects, out, Yield, Yield, g g g g% % CS-1 26.616 22.388 2.255 1.711 84.12 99.01 IP Mix 26.170 20.5731.376 3.770 78.61 98.28 CLWR_2 25.257 20.123 1.056 3.930 79.67 99.42CLWR_8.1 25.550 20.572 0.919 3.941 80.51 99.53

Results indicated that the accepts yield for all studied samples isclose to 80%. Sample CS-1 had the highest accepts yield and the leastamount of wash-out. This result may be due to the uncoating feature ofthe based paper sheet. For all the samples, the overall yield almostreaches 100%, indicating excellent recovery of the starting materials inthe three fractions. All the accepts had particles of impurities invarious sizes. Accepts of some samples also contain fragments ofplastics that may have been broken down from the plastic coating. Judgedfrom the reference ruler, the size of those particles is less than 1 mm.The rejects also contain small quantities of fibers. During the entireprocedure, was completed without the use of acid wash to clean the flatscreens in the repulpability tests or dismantling the pressure screensto clean them before finishing the recyclability test. Further, therewas no visible deposition on any part of the disintegrator during therepulpability test or anticipated in a recyclability test. It iscontemplated that the values shown in Table 12 above may vary by about±50%.

2. Compositions of the Three Fractions

Compositions of the fractions are divided into three categories: fibers,plastics and inorganics which may come from the fillers in the basepaper and the mineral coatings in the coating layers. Through the acidhydrolysis-ash operations, the fibers, plastics and inorganics can bedistinguished and quantified. This is based on the fact that fibers arecomposed of carbohydrates and they are readily hydrolyzed in sulfuricacid solution under elevated temperature. Plastics, however, aregenerally resistant toward such hydrolysis and will be recovered asinsoluble substances. In the ashing process, both fibers and plasticswill be burnt out. Inorganics survive this process and are recovered asash.

Table 15, below, lists the experimental results indicating thepercentage of each fraction in each sample.

TABLE 15 Percent Compositions of the Three Fractions Accepts RejectsWash-out Sample Ash Fibers Plastics Ash Fibers Plastics Ash FibersPlastics Ash CS-1 0.24 98.92 0.74 0.40 3.56 96.44 0.04 82.44 1.47 17.78IP Mix 8.18 92.18 3.21 4.75 1.05 89.28 9.22 68.43 2.56 29.01 CLWR_210.33 94.43 1.04 4.53 5.05 57.43 37.52 63.07 2.21 34.72 (94.17) (1.30)CLWR_8.1 8.43 94.42 1.00 4.58 10.59 54.87 34.54 61.82 2.79 35.39 (94.11)(1.31) Note: Data in parentheses are validation runs. Plastics columnscan represent either mineralized layer fragments or separated plasticmaterials or both. It is contemplated that the values shown in Table 15above may vary by about ±50%.

In order to obtain reliable results, analysis to accepts of sampleCLWR-2 and CLWR-8 was performed in triplet runs: a duplicate run toproduce the average result, and a third run in large sample size toserve as validation. As indicated, the majority of the accepts isfibers, accounting for over 92% of the mass. Ash and plastics are minorcomponents existing probably in the forms of small particles. Comparingto sample CS-1, all the accepts from other three samples contains higheramounts of inorganics. As to the plastics components, IP Mix hassubstantial high quantity than CS-1, whereas those among CS-1, CLWR-2and CLWR-8.1 are comparable. Plastics are the dominant components in therejects fraction, especially in sample CS-1. Sample IP Mix, CLWR-2 andCLWR-8.1 have increasingly amounts of inorganics in the rejects. It isnot known if these inorganics are closely packed inside the plastics orpresented as separated particles. In the washout, the fibers are themajor components, especially in sample CS-1 and IP MIX. Sample CLWR-2and CLWR-8.1 have increasingly amounts of inorganics, probably presentedas colloid particles in the washing liquor.

3. Stickies Analysis

Impurities in the accepts are the major concern in the recycled pulpfibers.

Although composition analysis in section 2 provides informationregarding these impurities, a visualized analysis can provide moresubtle features of the impurities. Stickies analysis (some of theparticles could also be referred to as “dirties”) is thus performed toreveal the particle content and their size distribution.

TABLE 16 Stickies Analysis Results CLWR-2 CLWR-8.1 Fibers RejectsWashout Fibers Rejects Washout Stickies, 108 n/a n/a 123 n/a n/a mm²/gRosin +++ + +++ +++ + +++ Starch + Not + + Not + detected detected

Table 16 stickie count is represented as a number of stickies containedin the accepts sampling prior to any further processing. Therefore, the3 gram hand sheets subsequently made from the accepts fibers contained100% of the stickies and other miscellaneous particles in the acceptsimmediately after pulping but before further cleansing or processingsuch as cleaning, flotation, etc. The hand sheets are pressed and driedat 350° F. and 500 psi on a Carver press for 5 minutes and tested forperformance consistent with TAPPI T 537, TAPPI T277, TAPPI T 220, TAPPI815, TAPPI T 826, TAPPI T 403, TAPPI T 831 and TAPPI T563. It iscontemplated that the values shown in Table 16 above may vary by about±50%.

Results shown in FIG. 11 indicate that contents of stickies in bothCLWR-2 and CLWR-8.1 are comparable. Particle size distribution plotsindicate that all the stickies have a size less than 0.4 mm². Allparticles having an area less than 0.05 mm² are dominant, withapproximately 80% or more of the particles 0.0015 mm² or less. Thisresult, however, is highly in line with what have been observed theaccepts for each sampling. Since no further processing e.g. cleaning,reverse cleaning, flotation, high density cleaning, sidewall washing,peroxide dispersion, sodium hydrosulfite bleaching, hydrosieve washing,or post flotation at specified pH levels, etc., of the accepts occurred,100% of the stickies or dirties residing in the unprocessed acceptspassed directly through to the handsheets. Upon completion of thehandsheets, no substantial or important visual or cosmetic differencefrom that of the virgin control board samples were seen. Thisexceptional cosmetic result is primarily a factor driven by the verysmall overall particle size and the white, opaque, color which closelymatches the bleached board SBS fibers found in the handsheets andcontrol samples. Further, 100% of the particles are less than or equalto 0.4 mm² and therefore would not be considered large enough forcosmetic considerations. It is expected that the mineralized boardtesting samples CS-1, IP MIX, CLWR 8.1 CLW 2 and the handsheets would beconsidered fully recyclable fibers based on structural, cosmetic, andother considerations including processability within about pH 6 to 8±0.5pH levels, fiber processing temperature levels from about 110° F. toabout 135° F., pulper consistency from about 1.2 to 30%, pulping timefrom about 10 minutes to about 40 minutes, fiber on fiber yield fromabout 60% to about 95% and hand sheet drying temperatures in the rangeof about 240° F. to about 290° F., with finished sheet moisture levelsfrom about 5% to 9%, recyclability testing methods in accordance withtesting standards established by TAPPI T220, T815, T826, T403, T831,T537, T277, T563.

4. Fate of Rosin Acids

Rosin is a collective name given to a group of chemicals includingabietic acid, pimaric acid, isopimirc acid, palustric acid,dehydroabietic acid, etc. The rosin used in the paper making process canalso be oxidized into different forms. Nonetheless, the acids arereadily extracted by using DCM in acidic medium, and can be easilyseparated by using a neutral GC capillary column.

Results of GC/MS analysis to the three fractions from sample CLWR-2 andCLWR-8.1 are shown in Table 16, above. FIG. 12 illustrates a typicaltotal ion spectrum of the DCM extract.

As indicated, the rosin acids are separated completely by GC. Judgedfrom the peak area, the fibers fraction contains the highest amount ofrosin, following by the washout and the rejects. It is contemplated thatthe values show in FIG. 8 may vary by about ±50%.

5. The Whereabouts of Starch

Starch's whereabouts among the three fractions is determined by iodinedetection. It is well known that starch will turn the iodine-containedsolution into blue color. Based on this phenomenon, starch is found inboth the fibers fraction and washout fraction, but not in the rejectsfraction, as indicated in Table 3.

Example 5

By weight 40% to 60% mineralized resins were applied via extrusioncoating were to uncoated and clay coated virgin bleached boards withweights from about 57 lbs per thousand square feet (msf) to about 77 msfand were repulped to produce three fractions: the accepts, the rejectsand the wash-out. A full study including repulpability, compositions ofdifferent fractions, stickies analysis, fate of rosin acids and starchwere performed. Results indicated that the accept yield was over 78%,and an overall recovery of almost 100% was reached when the accepts, therejects and the wash-out were compiled. In general, the accepts weredominated with fibers, which accounted for over 92% of the mass.However, small amounts of plastics and inorganics (fillers and coatings)were also present. The rejects were mainly plastics, but significantamount of inorganics were also found in some samples. The wash-outcollected from the washing liquor contained significant amounts offibers and inorganics with small portion of plastics. Stickies contentin the accepts without any cleaning, screening, washing, or flotationwas determined in mm²/g and was 108 and 123 respectively for sampleCWR-2 and CWR-8.1. The stickies or non-fiber particles were quite uniquein composition and do not fit the standard industry definition as such,for example, they were not comprised of adhesives, hot melts, waxes, orinks. They were instead comprised of small dense fragmented mineralparticles with varying amounts of PE bonding agent attached, formingprimarily structures appearing to be easily dispersed as individualparticles within the accepted fibers. Other characteristics includedrelatively high surface energy and little, if any, tackiness. Theyappeared to resist deformability and appeared to have little potentialto cause problems with deposition, quality of sheet, and processefficiency. The stickies and other various particles were predominentlyopaque and white in color, with densities projected to fall within arange from about 1.10 g/cm³ to about 4.71 g/cm³. Because of the natureof the stickies, higher processing pH levels or peroxide bleaching wouldnot have the effect of increasing tackiness. The majority of thestickies can be defined as “micro-stickies” as they particles sizes fellbeneath 150 microns in size and above 0.001 micron in size. Because ofthe benign nature of the stickie composition, it is expected they willhave little tendency to stick or adhere to equipment during processing.The data indicated that the rosin acids were found in almost all threefractions, but most of them associated with the accepts and thewash-out. An iodine detect technique found that the starch was in theaccepts and the wash-out, and the rejects was practically starch-free.

The composite structures described herein are well suited to be formedinto containers of various types. For example, FIG. 7 illustrates acontainer comprising a box 60. The box 60 may have many applications,such as, without limitation, retail and shipping. The box 60 may be inthe form of a cube or other parallelepiped that is sized to contain anitem for retail sale and/or shipping. The box 60 may be formed bypreparing the composite structure in the form of a pliable sheet, forexample by performing a milling step and/or other processing steps asdescribed above, cutting the structure into a desired shape, and thenfolding and/or creasing the sheet, either manually or by machine, suchas via an automated cartoning process, to form the finalthree-dimensional box shape. Abutting surfaces of the box 60 may besecured to one another using the various heat seal processes describedherein and/or other heat seal processes known in the art. In theembodiment shown in FIG. 7, the composite structure forms the walls ofthe box 60, including a bottom wall 62, one or more side walls 64, aswell as a fold-over lid portion 66.

In other embodiments, the composite structures described herein may beformed into a container liner 70 for retail and/or shipping use, asshown in FIG. 8. The liner 70 may be used to line a shipping or retailcontainer 72 to cushion and/or protect a product held in the container72, as well as to provide moisture resistance and deter infiltration ofrodents and other pests. The liner 70 formed of the composite structuremay be sufficiently flexible and pliable such that it is capable of atleast partially conforming to the shape of the container 72.

In other embodiments, the composite structures described herein may beformed into a shipping mailer 80, such as an envelope, which may be usedto ship documents and/or other items, as shown in FIG. 9. The compositestructure may be used to form a part of or even all of the mailerstructure 80, and may be fabricated by using a series of folding,creasing, and/or adhesive/heat seal steps to prepare the desired mailershape.

In other embodiments, the composite structures described herein may beformed into a display tray 90 and/or other sales displays, as shown inFIG. 10. For example, the composite structure may be cut, shaped, and/orfolded into the shape of a display tray 90 capable of holding anddisplaying products for retail sale. The composite structure can bemolded by bending and/or folding, as well as via thermo- and/orvacuum-forming to form desired parts of the display 90.

Other non-limiting examples of applications for which the presentembodiments are well suited are described in one or more of thefollowing publications, each of which is incorporated herein byreference in its entirety: U.S. Patent Application Publication Nos.2009/0047499, 2009/0047511, and 2009/0142528.

The above description presents various embodiments of the presentinvention, and the manner and process of making and using them, in suchfull, clear, concise, and exact terms as to enable any person skilled inthe art to which it pertains to make and use this invention. Thisinvention is, however, susceptible to modifications and alternateconstructions from that discussed above that are fully equivalent.Consequently, this invention is not limited to the particularembodiments disclosed. On the contrary, this invention covers allmodifications and alternate constructions coming within the spirit andscope of the invention as generally expressed by the following claims,which particularly point out and distinctly claim the subject matter ofthe invention.

What is claimed is:
 1. A method of manufacturing a heat sealable andrecyclable packaging structure, the method comprising: extrusion coatingreleased fibers with a plurality of polymer/particle fragmentscomprising a thermoplastic and particles, wherein the plurality ofpolymer/particle fragments have a mean surface area of 0.0005 mm² to 2mm² and a density of 1.01 g/cm³ to 4.75 g/cm³ wherein the extrusionprocess is carried out under the following conditions: thepolymer/particle fragments resin having a melt flow index from 4 g/10min to 16 g/10 min; a melt temperature from 590° F.±20%; an extruderscrew or tube barrel pressure from 1,200 psi to 2,500 psi; an air gapfrom 4″ to 16″; a die gap from 0.020″ to 0.050″; barrel and die zonetemperatures from 400° F. to 640° F.; and an extrusion lamination linespeed from 100 FPM to 3,500 FPM.
 2. The method of claim 1, wherein thepolymer/particle fragments have a mean surface area of from 0.01 mm² to2 mm².
 3. The method of claim 1, wherein the particles of thepolymer/particle fragments have a hardness of between 2.0 to 4.0 Mohsand an average surface area of from 1.0 m²/g to 1.3 m²/g.
 4. The methodof claim 1, wherein the particles of the polymer/particle fragments havea hardness of between 2.0 to 4.0 Mohs and an average surface area offrom 1.8 m² to 2.3 m².
 5. The method of claim 1, wherein the particlesof the polymer/particle fragments comprise mineral particles, andwherein the mineral particles are selected from the group consisting ofclay, kaolin, CaCO₃, mica, and silica.
 6. The method of claim 5, whereinthe mineral particles have a mean diameter of from 4 μm to 14 μm.
 7. Themethod of claim 1, wherein from 35% to 99% of the polymer/particlefragments have a mean surface area of 0.0005 mm² to 2 mm² and a densityof 1.01 g/cm³ to 4.75 g/cm³.
 8. The method of claim 1, wherein thereleased fibers comprise reusable fiber containing pulp that aresuitable for manufacture of new paper products.
 9. The method of claim1, wherein the released fibers comprise softwood fibers, hardwoodfibers, or a mixture of softwood and hardwood fibers.
 10. The method ofclaim 9, wherein the mixture of softwood and hardwood fibers comprisesfrom 5% to 95% softwood fibers.
 11. The method of claim 9, wherein themixture of softwood and hardwood fibers comprises from 25% to 90%softwood fibers.
 12. The method of claim 9, wherein the mixture ofsoftwood and hardwood fibers comprises from 5% to 95% hardwood fibers.13. The method of claim 9, wherein the mixture of softwood and hardwoodfibers comprises from 25% to 90% hardwood fibers.
 14. The method ofclaim 1, wherein the released fibers are derived from a paper having abasis weight of from 30 lbs/3000 sq. ft. to 200 lbs/3000 sq. ft. and athickness of from 0.010 inches to 0.036 inches.
 15. The method of claim1, wherein the polymer/particle fragments are dimensioned to passthrough 0.005 inch round hole or slotted pressure screens.
 16. Themethod of claim 1, wherein the thermoplastic has a physical melt flowindex of from 4 g/10 min to 16 g/10 min.